nand2/06_IO_Devices/Readme.md

06 IO Devices

Build the following special function register to connect HACK to I/O-devices: UART_TX, UART_RX, SPI, SRAM, GO, LCD and RTP. For every special function register we provide a folder with implementation details and a testbench. The special function register must be memory mapped, so HACK can read/write data from/to the IO-device.

address	I/O dev	function
4096	LED	0 = led off, 1 = led on
4097	BUT	0 = button pressed "down", 1 = button released
4098	UART_TX	transmit byte to UART with 115200 baud 8N1
4099	UART_RX	receive byte from UART with 115200 baud 8N1
4100	SPI	read/write spi flash memory chip
4101	SRAM_ADDR	address of external SRAM chip
4102	SRAM_DATA	read/write data from/to external SRAM chip
4103	GO	Start execution of instructions from external SRAM
4104	LCD8	write 8bit command/data to LCD screen
4105	LCD16	write 16bit data to LCD screen
4106	RTP	read/write byte from/to resistive touch panel
4107	DEBUG0	used for debugging
4108	DEBUG1	used for debugging
4109	DEBUG2	used for debugging
4110	DEBUG3	used for debugging
4111	DEBUG4	used for debugging

For every special function register we will need the appropriate software to talk to the device. The simpler device drivers (UART, SPI, SRAM and GO) can be implemented in assembler. After completing the devices UART, SPI, SRAM and GO we will be able to fill the SRAM chip with up to 64K words (16bit) of HACK code. This will enable us to run JACK-OS and applications on HACK. The more sofisticated device drivers for LCD and RTP will be implemented in JACK language.

Proposed implementation

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Project

• Copy HACK.v from 05_Computer_Architecture into 06_IO_Devices and add one IO-Device at time at the designated memory mapped address. Implement the corresponding special function register and run the test bench.

  $ cd 0X_device
  $ apio clean
  $ apio sim
  

• Implement the designated assembler program, install the binary into 00_HACK and run the testbench:

  $ cd 0X_device
  $ make
  $ cd ../00_HACK
  $ apio clean
  $ apio sim
  

• Run HACK in real hardware on iCE40HX1K-EVB with the device attached as real device.

  $ cd 00_HACK
  $ apio clean
  $ apio upload
  

• Check if attached IO-Device is working accorging to the uploaded software.