6.8 Page 4: dsPIC Interface

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Page 4, Base + 12 Read/Write dsPIC Data Register

PICR/W	Read/write control: 0 = write, 1 = read
PICA4-0	dsPIC internal address

Writing a byte with R/W = ‘0’ will cause the dsPIC to write the data contained in the dsPIC Data Register above to the dsPIC internal address indicated by PICA4-0. Writing a byte with R/W = ‘1’ will cause the dsPIC to read the data at dsPIC internal address, PICA4-0 and place the received data in the dsPIC Data Register.

Page 4, Base + 13 Read dsPIC status register

I2CBSY	I2C port status bit:
0	Last I2C operation completed
1	Last I2C operation in progress
PICA4-0	dsPIC address last accessed

Page 4, Base + 14 Write Auto-Autocalibration Command Register

Only one bit can be set to ‘1’ at once. Bits are processed MSB to LSB. The first ‘1’ determines which command is carried out.

ACHOLD	1 = Auto-autocal process is disabled. Autocalibration must be triggered by software
ACREL	1 = Auto-autocal process is enabled. Auto-autocalibration will occur whenever the board requires it.
PICRST	1 = Reset dsPIC device. This command is normally not needed.
ACABT	1 = Abort any currently running auto-autocal operation immediately
ACTRIG	1 = Initiate an auto-autocal process immediately

Page 4, Base + 14 Read Auto-Autocalibration Status Register

ACHOLD	1 = dsPIC in holdoff mode (auto-autocal disabled)
PICPRST	1 = dsPIC device present on board
ACERR	1 = dsPIC detected errors during last Auto-autocal process
ACACT	1 = Auto-autocal process currently in progress
PICBSY	1 = dsPIC busy, either with auto-autocal or some other activity

Details concerning auto-autocalibration can be found at in chapter 15 on page 48.

Page 4, Base + 15 Write dsPIC Programming Register

This register is used to control the on-board dsPIC microcontroller. The dsPIC controls the auto-autocalibration process, and it also provides the communication link between the board and its serial port. The bits in this register are control bits, not register bits. Only one bit can be set to ‘1’ at once. Bits are processed MSB to LSB. The first ‘1’ determines which command is carried out

PSTART	Drive EN_PROG# signal low.
PSTOP	Drive EN_PROG# high.
PGDOUT	FPGA makes PIC_PGD line an output, but leave at current level (i.e. perform input to find current level, set line as an output at same level.)
PGDIN	FPGA makes PIC_PGD line an input.
PGDW1	If PIC_PGD line is in output mode, set high
PGDW0	If PIC_PGD line is in output mode, set low
PGCW1	Set PIC_PGC line high
PGCW0	Set PIC_PGC line low

Page 4, Base + 15 Read dsPIC Programming Register

PGDR Reads back current level of PIC_PGD line (low = 0, high = 1)