File format specification of configuration definition

this describes the possible elements of a configuration description in JSON format.

The JSON format is defined here: https://www.json.org/json-en.html

All elements not listed as essential are optional. Being optional means that they can be missing and the configuration is still valid.

If elements that describe a peripheral are not present than that peripheral will not be used. No initialization code for that peripheral will be generated.

If elements that define general settings are missing then the default value for that setting is used. The section describing the element will also state the default value.

The essential elements are :

• vendor_name
• chip_name

The settings defined in this file cover different areas.

• general settings
• peripheral settings
  • driver layer
  • signal names

general settings affect the whole project. These settings are general configurations and switches to enable additional features or to select modes for the project.

peripheral settings are definitions of peripheral configuration. Examples are Pad names, enabled or disabled functionality and Speed settings.

The peripherals can be used in different ways (polling, interrupt, DMA) and for different purposes (“send text”, “send binary packets”, “fixed length packet”, “variable length packet”) and implementing these functionality is device independent. This configuration file should therefore only give guidance to MBSP and select the API style the user want's to use.

The user shall not be bothered with the details of the used peripheral. The user should therefore not depend on peripheral names (“SPI0”, “UART3”, “GPIO PA9”, ..) but refer to these resources by names that make sense for the user. These names are defined in this file.

{
    "vendor_name": "Geehy",
    "chip_name": "APM32F411VC",
    "digital_output": {
        "green_led": {
            "type": "push pull",
            "pad": "PA3"
        }
    }
    "SPI": {
        ...
    }
}

Keys like *digital_output* and *SPI* represent group names and are taken from a predefined set of group names understood by MBSP. Keys nested within them are arbitrary user-defined names for a instance in that group. In those instances the keys are from the defined set specific for that group.

these are settings on the top layer that effect the whole project.

Name of the company that sells the micro controller. As listed on https://chipselect.org

type: string

Model number of the micro controller. As listed on https://chipselect.org

type: string

Model number is truncated so that it only contains relevant differences for code generation: flash and ram sizes are relevant, temperature range or package are not.

what type of project to generate.

type: string

default: “make”

Possible values are:

• “hal only” : only creates the hardware driver files (in the hal/ folder) and hardware definitions (in the hal/hw/ folder)
• “embeetle” : create an Embeetle IDE project
• “make” : creates a makefile based “blinky” project.

defines the comment at the top of each generated file.

type: string

default: “created”

Possible values are:

• “created” : file comment list date and time of file creation as well as configuration file name.
• “minimal” : short comment only stating the file name and that it was automatically created.

defines the location of the firmware code when run.

type: string

default: “flash”

Possible values are:

• “flash” : firmware is located and run from the flash memory.
• “ram” : firmware is located and run from the RAM.
• “flash2ram” : firmware is located in flash, copied to RAM on boot and then executed from RAM.

if you use a “hal only” MBSP project located in a sub folder of your project then the name of the sub folder goes here.

type: string

default: “”

configuration of the used clocks.

    "clock": {
        "cpu": {
            "source" : "hse",
            "frequency" : "12 MHz",
        }
    }

defines the source of the clock signal. Supported clock sources are:

• “hse” (High speed external)
• …

type: enum

default: hse

defines the frequency that this clock has.

type: string (Hz, kHz, MHz)

default: “1 MHz”

This group contains all digital output signals.

Each signal is a sub group with the signal name as the group name.

    "digital_output": {
        "green_led": {
            "type": "push pull"
            "pad": "PA3"
        }
    }

defines what type of output mode should be used. Type can be:

• push pull
• open drain

type: enum

default: push pull

defines the chip pad that the signal should be output on.

type: string

default: no default possible

If this setting is set to “on” then turning this output “on” will generate a Low (Gnd) signal. Turning it “off” will generate a High (Vcc) level.

If this setting is set to “off” (=default) then turning this output “on” will generate a High (Vcc) signal. Turning it “off” will generate a Low (Gnd) level.

type: string

default: “off”

This group contains all digital input signals.

Each signal is a sub group with the signal name as the group name.

defines the chip pad that the signal should be read from.

type: string

TBD

TBD

This group contains all timer and counter peripherals.

    "timer": {
        "ms_tick": {
            "peripheral" : "systick",
            "mode" : "count overflows",
            "frequency" : "1 kHz",
        }
    }

defines which peripheral to use. peripherals can be:

• systick (part of the ARM core)
• timer1
• timer2
• …

type: String

default: systick

defines the operation mode the timer/counte operates in. Possible modes are:

• count overflows

type: enum

default: count overflows

The frequency defines the time between timer overflows. 1kHz means that the time between overflow events is 1/(1 kHz) = 1 ms.

type: string (Hz, kHz, MHz)

default: “1 kHz”

TBD

This group defines all used Universal Asynchronous Receiver Transmitter (UART) interfaces.

Each UART is a sub group with the UART name as the group name.

    "UART": {
        "debug_uart": {
            "pad_tx": "PA5",
            "pad_rx": "PA6",
            "pad_cts": "PA7",
            "pad_rts": "PA15",
            "bits_per_packet": "8",
            "parity": "None",
            "stop_bits": "1",
            "baud_rate": "115200",
            "hardware_flow_control": "no",
            "receive_buffer_size": "100",
            "send_buffer_size": "500",
            "peripheral" : "UART0",
            "IRQ" : "20", 
            "IRQ_priority" : "0",
        }
    }

The UART will send data on this pin. (Idle = High). Either this or the pad_rx must be given.

The UART will receive (read) signals on this pin. Either this or pad_rx must be given.

Clear to send signal for flow control. Will not be used if not defined.

Request to Send signal for flow control. Will not be used if not defined.

defines the number of data bits. Possible values are:

• 7
• 8
• 9

type: enum

default: 8

defines the parity bit. Possible values are:

• None : no parity bit used.
• Odd : the parity bits value makes sure that the packet contains an odd number of bits with value “1”.
• Even : the parity bits value makes sure that the packet contains an even number of bits with value “1”.

type: enum

default: None

defines the number of stop bits. Possible values are:

• 1
• 1,5
• 2

type: enum

default: 8

defines the number of bits send per second.

type: int

default: 115200

defines if the Request to Send (RTS) and Clear to send (CTS) signals should be used for flow control. Possible values are:

• off (RTS and CTS pins are not used.
• RTS only
• CTS only
• on (RTS and CTS signals are used)

type: enum

default: off

defines the number of bytes in the receive buffer of the driver.

type: int

default: 100

defines the number of bytes in the send buffer of the driver.

type: int

default: 500

name of the UART peripheral to use.

type: String

The interrupt number of the peripheral.

type: int

The interrupt priority of the interrupt.

type: int

This group defines all used Serial Peripheral Interface (SPI) interfaces.

Each SPI interface is a sub group with the SPI name as the group name.

    "SPI": {
        "encoder_spi": {
            "pad_sck": "PA5",
            "pad_miso": "PA6",
            "pad_mosi": "PA7",
            "pad_ncs": "PA15",
            "role": "master",
            "communication_mode": "duplex",
            "frame_format": "motorola",
            "clock_polarity": "idle_low",
            "clock_phase": "sample_on_leading_edge",
            "bit_order": "msb_first",
            "baud_rate": "10 MHz",
        }
    }

Serial Clock.

“Master Out Slave In” data signal.

“Master In Slave Out” data signal.

Chip Select signal (Low active).

Is either master(host) or slave(device).

type: enum

default: master

Describes the communication. Possible values are:

• duplex : the traditional mode using MISO and MOSI to transmit and receive at the same time.
• half-duplex : meaning the same wire between master and slave is used for both directions.
• receive-only : send line is not used
• send-only : receive Line is not used.

type: enum

default: duplex

Describes the communication. Possible values are:

• motorola : the “normal” SPI.
• ti :

type: enum

default: motorola

Also often called CPOL. Describes the communication. Possible values are:

• idle_low
• idle_high

type: enum

default: idle_low

Also often called CPHA. Describes the communication. Possible values are:

• sample_on_leading_edge : samples the data on the edge from idle value to non-idle value.
• sample_on_trailinging_edge : samples the data on the edge from non-idle value to idle value.

type: enum

default: sample_on_leading_edge

Sometimes the documentation talks about a SPI Mode with the value of 0 to 3. This mode maps to the phase and polarity as described in the following table:

Describes the communication. Possible values are:

• msb_first : most significant bit first (bits on the line : 76543210 )
• lsb_first : least significant bit first (bits on the line: 01234567 )

type: enum

default: msb_first

Is the number of bits per second exchanged on the data lines. Expressed as frequency of the clock line.

type: int (Hz)