PSOC Unused I/O Pins

Summary

This blog reviews GPIO configurations for unused PSoC microcontroller pins with a focus on the resulting differences in current usage.

Cypress PSoC4 Controller

Existing Literature
Information relating to the handling of unused pins can be located for most microcontrollers, for example AVR or Microchip. Companies such as Analogue Devices have posted similar unused pin information in their monthly Analog Dialogue.

Between the Cypress Technical Reference Manuals (TRM) and the Cypress community forum, methods for handling unused processor pins have been detailed or discussed in numerous times.  Forum suggestions for managing unused pins varies from configuring the pins as high impedance digital inputs, to resistive pull-up/pull-down to outputs.

The PSoC4 TRM states on page 64 under the High Impedance Analogue heading that unused GPIO pins should be configured as high impedance analogue pins (PSoC 4100/4200 Family PSoC 4 Architecture TRM, Document Number: 001-85634 Rev. *H).

While the TRM does not detail the benefits of terminating unused pins with pull-up / pull-down resistors or the effects of EMC / EMI on floating pins, one of the salient remarks in the extract from the TRM is 'unused GPIOs must be configured to the high-impedance analog'. The previous comment relates primarily to current consumption in low-power modes, however the pin configuration could be inferred for unused pins.

High-Impedance Analog
High-impedance analog mode is the default reset state; both output driver and digital input buffer are turned off. This state prevents an external voltage from causing a current to flow into the digital input buffer. This drive mode is recommended for pins that are floating or that support an analog voltage. High-impedance analog pins cannot be used for digital inputs. Read-ing the pin state register returns a 0x00 regardless of the data register value. To achieve the lowest device current in low-power modes, unused GPIOs must be configured to the high-impedance analog mode.

For pins configured as high impedance (digital), Electronic Design is one of the sites which details the reason why high impedance digital inputs are not preferred. An extract from the Electronic Design site is detailed below.

Over time, however, the floating input tends to accumulate a charge and float toward the logic level change-over point. When it reaches that point, it causes both the high and low MOSFETs to be partially on, resulting in shoot through current.

To provide a visual representation of shoot through current mentioned in the above extract, consider a post such as this from the Texas Instrument forum.

Shoot Through Current - Courtesy Texas Instruments

Certainly other technical sources indicate that pin configurations should be resistively biased or configured as outputs only. Time to perform a few measurements to verify the pin configurations!

PSoC Current Measurements 
To perform current measurements of the PSoC4 on the bench, a surplus PCB from a previous project was loaded with minimal components. A PSoC4, a pull-up resistor for the reset line and some essential capacitors were fitted to the board.

Cypress Microcontroller with Unused Pins

PSoC Programming was performed using a Miniprog.

The supply (5 VDC) was provided from a bench supply, Rigol DP832, as shown in the image below. Current measurement was made using a standard digital multimeter.

PSoC4 Bench Setup for Current Measurement

The PSoC Creator application used the pin component to configured the entire port. Any change made to the pin type was reflected for all pins on the port.

PSoC Creator Top Design All Pin Configuration

Two current measurements were taken as verification. The power supply current measurement was verified against the multimeter.

Measurement Results
Measurements were performed on a PSoC4 (CY8C4245AXI-483) with GPIO drive modes (type) 0 - 4 and 6 - 7.

PSoC4 GPIO Drives Modes - Courtesy Cypress Semiconductor

For the GPIO types listed in the table below, the default PSoC Creator settings were used. All pins were configured for contiguous mapping except for high impedance analogue inputs which required the contiguous mapping to be disabled.

PSoC4 Overall Current Measurement for GPIO  Configurations

The High Impedance Digital Input GPIO type had a striking difference in measured current compared to the other types.

Final Thoughts 
High Impedance Digital Inputs resulted in the highest overall current consumption of an active PSoC4 device. From the brief range of measurements performed in this post it would be prudent not to configure unused PSoC pins as High Impedance Digital.

Unused PSoC pins should be configured with internal resistor biasing or as outputs where practicable.

PSoC Project
For readers interested in verifying or disprove this post, the PSoC Creator project is made available.

PSoC Creator Project - Test PSoC

Rexon RDM150D Retrofit ESTOP Stage 2

Summary

This blog details the second stage retrofit of a Rexon RDM150D drill press. The second stage added movement monitoring of the spindle and a requirement to  deactivate the drill press run switch after triggering the ESTOP. The first stage retrofit blog contained details relating to controller design and the drill press wiring.

Electrical Wiring - Stage 1

The first stage changes to the drill press electrical, which included the ESTOP button and controller, are shown in the image below.

Rexon RDM150D Stage 1 Electrical

Electrical Wiring - Stage 2

For the second stage retrofit, a proximity switch and a relay were added to the design. Both the new devices were connected to the controller.

Rexon RDM150D Stage 2 Electrical

Inductive Sensor

For detection of rotational movement in the pulley responsible for driving the spindle, an inductive sensor was selected.

      MCPIP-T12L-001 Courtesy Multicomp

The sensor was manufactured by Multicomp, part MCPIP-T12L-001, which features a PNP output, M12 thread and a 2mm sensing distance.

Inductive Sensor PNP Electrical Connections

DIN Relay
A relay was added to detect when the manual switch (DPDT) was in the ON state. Providing the manual switch state to the controller served two purposes, firstly the controller could determine when the spindle was active and secondly the same feedback signal could be used to ensure that the manual switch was OFF before the contactor was reactivated.

DIN Relay 2909526 Courtesy Phoenix Contact

The relay used was a DIN style, 240V input, from Phoenix Contact.

As shown in the second stage electrical drawing above, the input to the relay was driven from the equipment side of the manual ON OFF switch. The pair of secondary side relay Normally Open connections were individually connected to 24V and the Spindle Active input of the controller.

Sensor Hardware and Mounting

An oversight with the Multicomp sensor installation was the devices body length which prevented the sensor being mounted between two pulleys.

Sensor Mounting Bracket

To mount the sensor inside the top housing of the drill press, a repurposed wall bracket was drilled to the required hole size (M12). Loctite 243 was used on the sensor thread. The bracket was fitted at an angle as shown in the above image. This prevented use of the lowest belt position between the spindle and middle pulleys. A shorter sensor, placed parallel to the belts, would be recommended for those implementing this design.

Triggering the sensor was achieved using a small steel angle fitted to the pulley. For a speed of 3000 RPM, best results were achieved when the length of the steel angle was 20 mm. Two M3 bolts with Loctite 243 and internal star washers were used to fix the steel bracket in position.

Sensor Steel Pulley Bracket

Sensor Test Measurement

With the Multicomp sensor powered and an Oscilloscope fitted to the Out connection, one measurement was taken at a slow RPM and the second measurement at the fastest RPM.

Slow RPM Sensor Measurement

Fast RPM Sensor Measurement

Relay Mounting

The DIN relay was mounted between the contactor and the controller, as pictured below.

Electrical Enclosure DIN Relay Mounting

PSoC Inputs
The spindle and spindle active inputs to the PSoC controller were provisioned in the first stage controller design. Connections were made according to the updated inputs detailed in the section below.

PSoC Inductive Spindle Input

Controller Wiring
A correction was required to the controller PCB overlay. The capture below shows the updated overlay reflecting the controller connections.

Retrofit Rexon Controller Updated PCB Overlay

Controller Option
To identify new features were added to the controller, one of the option resistors was populated on the controller PCB.

Enabling Controller Option on PCB

PSoC Code Changes

The principal change to the PSoC was the addition of logic for counting pulses from the inductive sensor.

PSoC Windowed Pulse Counter

A timer solution was implemented fifty percent duty cycle with a period of 499 ms. During the On time the Timer_Spindle component accumulated counts from the Spindle input. At the end of the capture the isr_Spindle fires allowing the count value to be retrieved. For the remainder of the period no counting was performed. The Sync component was used to synchronise the slower PWM_Spindle clock with the Timer_Spindle clock.

Monitoring of the spindle active input and spindle speed was moved into a basic state machine, extract listed below.

/**
* @brief Basic State Machine for handling ESTOP and Spindle signals
*/

void State_Mach_Mon(void) 
{
    switch (Spindle_Monitor_State)
    {
    case (state_m_idle):
        if (Status_ESTOP_Read() == 1u)
        {
            Spindle_Monitor_State = state_m_es_deact;
        }
    break;

   case (state_m_es_deact):
        Control_ESTOP_Write(0x1); 
        if (Status_ESTOP_Read() == 0u)
        {
            Spindle_Monitor_State = state_m_reset;
        }

        if (Spindle_Active_Read() == true)
        {
            PWM_Spindle_Start();
            Timer_Spindle_Start();
            Spindle_Monitor_State = state_m_es_sp_act;
            Spindle_Started = true;
            Spindle_Timer = 100u; 
        }
    break;

    case (state_m_es_sp_act):
        Spindle_Count_Update();
        if (Status_ESTOP_Read() == 0u)
        {
            Spindle_Monitor_State = state_m_es_reset;
        }

        if (Spindle_Active_Read() == false)
        {
            Spindle_Monitor_State = state_m_reset;
        }

        if ((Spindle_Counts == 0) && (Spindle_Timer == 0))
        {
           Spindle_Monitor_State = state_m_es_reset;
        }
    break;

    case (state_m_es_reset):
        PWM_Spindle_Stop();
        Timer_Spindle_Stop();
        Control_ESTOP_Write(0x0); 
        Spindle_Started = false;
        if (Spindle_Active_Read() == false)
        {
            Spindle_Monitor_State = state_m_idle;
        }
    break;       

    case (state_m_reset):
        Control_ESTOP_Write(0x0);
        PWM_Spindle_Stop();
        Timer_Spindle_Stop();
        Spindle_Monitor_State = state_m_idle; 
    break;
    } 
}

Additional changes were made in the code to read pulses measured by the spindle sensor counter and also to determine the configuration of the PCB version (function) resistors.

Option Resistors
Notes for the code option resistors was into the PSoC project.

PSoC Notes for Option Resistors

In the PSoC code, the various resistor combinations were used to define the controller operation.

/**
* @brief Board Options
*/
void Board_Options(void)
{
    if ((Option0_Read() == false) && (Option1_Read() == false))
    {
        System_Flags.Option_None = true;
        UART_UartPutString("No option\r\n");
    }
    else if ((Option0_Read() == true) && (Option1_Read() == false))
    {
        System_Flags.Option_Spd_Mon = true;
        UART_UartPutString("Speed monitor option\r\n"); 
    }
    else if (((Option0_Read() == true) && (Option1_Read() == true)) || ((Option0_Read() == false) && (Option1_Read() == true)))
    {
        UART_UartPutString("Unknown option\r\n"); 
    }
}

Sensor Counts
As the pulse counter configuration provided a 250 ms sampling window, the multiplier for the number of counts was set to 240.

/**
* @brief Read Spindle Counts and Report
*/
void Spindle_Count_Update(void) 
{
    if ((Spindle_Data_Ready == true) && (Spindle_Started == true))
    { 
        Spindle_Counts = Spindle_Raw*240u;
        Spindle_Data_Ready = false;
        ReportData();
    }
    Flag_Timer = false;
}

The Report Data function was used to provide the spindle speed in RPM. Data was output on a UART as shown in the capture below from TeraTerm.

Controller Spindle Speed Output in TeraTerm

A timer, defined by variable Spindle_Timer, ensured that when the spindle was not spinning for one second, the drill press motor would be switched off using the contactor.

Final Thoughts

The controller in this blog could be adapted for other workshop machinery, which was not originally manufactured with a method to stop that machinery in a controlled manner. Features such as the spindle rotation monitoring could be removed or disabled and other features added to suit the machine setup.

Downloads

ESTOP v1.1 BOM XLS

ESTOP v1.1 Schematics PDF

ESTOP v1.1 PCB PDF

ESTOP v1.1 Gerbers

ESTOP  v1.1 PSoC Doxygen

ESTOP v1.1 PSoC 4.3 Project

ESTOP Module PSoC Creator Top Design PDF

PSoC Creator gitignore update

Summary

This blog expands on listings shown in several posts which provide details for GIT ignore files for PSoC Creator. When using GIT with an IDE such as PSoC Creator, the .gitignore file defines which files are required for the project and which files can be ignored. Details regarding the use of the ignore feature is available in numerous places, Atlassion being one of them.

Examples shown in this blog cover PSoC 4 and PSoC 6 projects.

Existing Solutions
Below are the links to a few existing GIT ignore solutions for use with PSoC Creator and standard PSoC4 projects.

https://github.com/SorenHN/PSoC-gitignore/blob/master/.gitignore
https://github.com/github/gitignore/pull/2086/commits/7ffe05303d632f226d091f46079f1aa9cff933e9
https://git.2li.ch/various/gitignore/commit/5a355ed010640b689e06c589e38019bff81c9a15

Ignore File Additions

For Bootloadable PSoC 4/5 or PSoC6 projects, some additions were required to the existing ignore files.

# PSoC Creator 4.3
# Updated by  : GregL
# Dated   : 12/03/2020
# Details   : Place this ignore file together with cywrk or alter directories to match the required structure

# PSoC Creator Folders to ignore (PSoC4/5)
*Archive/
*Backup/
*codegentemp/
*CortexM0/
*CortexM3/
*Export/
*Generated_Source/

# PSoC Creator Folders to ignore (PSoC6)
*armgcc/
*CortexM0p/
*CortexM4/
*iar/
*mdk/

# PSoC Creator Non-Bootloadable project files to ignore (PSoC4/5)
*_timing.html
# Bootloadable project files to ignore
**.cydsn/*timing.html
*.svd
*.rpt
*.cyfit
*.cycdx
*.log
*.tmp
*.txt

# PSoC Creator Non-Bootloadable project files to ignore (PSoC6)
*.icf
*.ld
*.scat

# Option for .ctl files used in some PSoC Creator examples
#*.ctl

# Option for .pdf files supplied by some PSoC Creator examples or those specifically created from Creator
#*.pdf
#*_datasheet.pdf

# Optional PSoC Creator Files to ignore (Export to IDE feature)
*.mk
makefile

# PSoC Creator User Files to ignore
*.cyprj.*
*.cywrk.*

# For external editors such as NotePad+++
*.bak

As with many ignore files, some level of customisation is usually required to suit the project.

gitignore file

Testing Summary
To confirm the ignore file operation with PSoC Creator 4.3, three example projects were used from Code Examples in PSoC Creator. Two of the examples were PSoC 4 projects, one a standard application and the other a bootloader bootloadable application. The third test used a PSoC6 example.

Testing with SourceTree (PSoC4)
For a standard PSoC4 project the top folder in Windows may be similar to the example shown below.

Example PSoC4 Project Top Folder

Inside the project design folder are generated files and source folders. There are specific files required for PSoC Creator projects as detailed by Cypress.

Example PSoC4 Project Design Folder

Using the ignore file with PSoC4 project in SourceTree yields the result displayed below.

Example PSoC4 Project in SourceTree using gitignore

Testing with SourceTree (PSoC4 Bootloadable)
For a PSoC4 project with bootloader and bootloadable application, the top folder in Windows may be similar to the example shown below.

Example PSoC4 Bootloader Project Top Folder

Inside the project Bootloader design folder are generated files and source folders.

Example PSoC4 Project Bootloader Design Folder

This is the same for the Bootloadable design folder.

Example PSoC4 Project Bootloadable Design Folder

Using the ignore file with PSoC4 project in SourceTree yields the result displayed below.

Example PSoC4 Bootloader Project in SourceTree using gitignore

Testing with SourceTree (PSoC6)
For a standard PSoC6 project the top folder in Windows may be similar to the example shown below.

Example PSoC6 Project Top Folder

Inside the project design folder are generated files and source folders.

Example PSoC6 Project Design Folder

Using the ignore file mentioned in the previous section with PSoC6 project in SourceTree yields the result displayed below.

Example PSoC6 Project in SourceTree using gitignore

Final Thoughts
Using an ignore file with version control software such as GIT can ensure that only pertinent files to build a project are retained. The ignore file configuration however should be reviewed when projects change and if a new release of the associated IDE software replaces a prior release.

The ignore file provided in this blog for GIT projects is therefore always a work in progress!

Bosch Dishwasher Test Program SMS63M08

Summary

This blog details how the test program for a Bosch dishwasher model SMS63M08 is started. It should be stated that content in this post was derived from a video on similar Bosch dishwashers. All credit to SamuraiRepairman for details in the video.

Enabling Bosch Test Program

With the Bosch dishwasher switched off press any two wash programs then the ON/OFF power button, as shown by green in the image below.

Bosch SMS63M08

The display on the Bosch will flash on for a moment then display P0. Two of the LEDs should be illuminated, as displayed below.

Bosch SMS63M08 Test Program (P0)

Press the button Pots/Pans and the display will change to P1. One LED will remain illuminated.

Bosch SMS63M08 Test Program (P1)

Press the button Pre-rinse and the test program will begin. The display shows an S with a number which appears to be a timer.

Bosch SMS63M08 Running Test Program

The test program runs for over 20 minutes after which any errors are displayed.

Bosch SMS63M08 Test Program End

For a description of any error code see sites such as Bosch Dishwasher Error Codes.