Skip to content

Latest commit

 

History

History
239 lines (192 loc) · 7.07 KB

datasheet.md

File metadata and controls

239 lines (192 loc) · 7.07 KB
Raw

Datasheet

Overview

The i2c(inter-integrated circuit) IP is a fully parameterised soft IP to implement the standard i2c master interface. The IP features an APB4 slave interface, fully compliant with the AMBA APB Protocol Specification v2.0.

Feature

  • Compatible with Philips I2C standard
  • Programmable prescaler
    • max division factor is up to 2^16
  • 100Kbps, 400Kbps or 1Mbps support
  • 7 bits addressing mode only
  • Single master mode only
  • Maskable send or receive interrupt
  • Static synchronous design
  • Full synthesizable

Interface

port name type description
apb4 interface apb4 slave interface
i2c -> interface i2c slave interface
i2c.scl_i input i2c clock input
i2c.scl_o output i2c clock output
i2c.scl_dir_o output i2c clock tri-state ctrl
i2c.sda_i input i2c data input
i2c.sda_o output i2c data output
i2c.sda_dir_o output i2c data tri-state ctrl
i2c.irq_o output i2c irq output

Register

name offset length description
CTRL 0x0 4 control register
PSCR 0x4 4 prescaler register
TXR 0x8 4 transmit register
RXR 0xC 4 receive register
CMD 0x10 4 command register
SR 0x14 4 state register

Control Register

bit access description
[31:8] none reserved
[7:7] RW EN
[6:6] RW IEN
[5:0] none reserved

reset value: 0x0000_0000

  • EN: function enable

    • EN = 1'b0: i2c function disable
    • EN = 1'b1: otherwise

  • IEN: interrupt enable

    • IEN = 1'b0: interrupt disable
    • IEN = 1'b1: otherwise

Prescaler Reigster

bit access description
[31:16] none reserved
[15:0] RW PSCR

reset value: 0x0000_FFFF

  • PSCR: 16-bit prescaler value

Transmit Reigster

bit access description
[31:8] none reserved
[7:0] RW DATA

reset value: 0x0000_0000

  • DATA: transmit data
    • [7:1]: upper 7 bits of DATA
    • [0:0]: LSB of DATA
      • address phase: 0 -> write to slave 1 -> read from slave
      • data phase: LSB of DATA

Receive Reigster

bit access description
[31:8] none reserved
[7:0] RO DATA

reset value: 0x0000_0000

  • DATA: receive data

Command Reigster

bit access description
[31:8] none reserved
[7:7] WO STA
[6:6] WO STO
[5:5] WO RD
[4:4] WO WR
[3:3] WO ACK
[2:1] none reserved
[0:0] WO IACK

reset value: 0x0000_0000

  • STA: start command

    • STA = 1'b0: dont send start command
    • STA = 1'b1: otherwise

  • STO: stop command

    • STO = 1'b0: dont send stop command
    • STO = 1'b1: otherwise

  • RD: read from slave command

    • RD = 1'b0: dont send read command
    • RD = 1'b1: otherwise

  • WR: write to slave command

    • WR = 1'b0: dont send write command
    • WR = 1'b1: otherwise

  • ACK: read acknowledge

    • ACK = 1'b0: send nack command
    • ACK = 1'b1: send ack command

  • IACK: interrupt acknowledge

    • IACK = 1'b0: dont clear interrupt ack flag
    • IACK = 1'b1: otherwise

State Reigster

bit access description
[31:8] none reserved
[7:7] RO RXK
[6:6] RO BSY
[5:5] RO AL
[4:2] none reserved
[1:1] RO TIP
[0:0] RO IF

reset value: 0x0000_0000

  • RXK: receive acknowledge from slave

    • RXK = 1'b0: receive ack
    • RXK = 1'b1: otherwise

  • BSY: i2c bus busy

    • BSY = 1'b0: detect stop command
    • BSY = 1'b1: detect start command

  • AL: arbitration lost

    • AL = 1'b0: dont lost arbit
    • AL = 1'b1: otherwise

  • TIP: transmit in progress

    • TIP = 1'b0: transmit done
    • TIP = 1'b1: otherwise

  • IF: interrupt flag

    • IF = 1'b0: interrupt is triggered
    • IF = 1'b1: otherwise

Program Guide

These registers can be accessed by 4-byte aligned read and write. C-like pseudocode init operation:

i2c.PSCR = PSCR_16_bit // set the prescaler value
i2c.CTRL.EN = 1        // enable i2c core

write operation:

i2c.TXR = (SLAVE_ADDR_7_bit << 1) | 0 // send slave device addr
i2c.CMD.[STA, WR] = 1                 // set start and write mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')


i2c.TXR = SLAVE_SUB_ADDR_8_bit        // send slave sub addr
i2c.CMD.WR = 1                        // set start and write mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')

...
i2c.TXR = DATA_8_bit                  // send data
i2c.CMD.WR = 1                        // set start and write mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')
...

i2c.CMD.STOP = 1                      // send stop command
while (i2c.SR.BSY == 1)               // wait bus idle

read operation:

i2c.TXR = (SLAVE_ADDR_7_bit << 1) | 0 // send slave device addr
i2c.CMD.[STA, WR] = 1                 // set start and write mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')


i2c.TXR = SLAVE_SUB_ADDR_8_bit        // send slave sub addr
i2c.CMD.WR = 1                        // set start and write mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')

i2c.CMD.STOP = 1                      // send stop command
while (i2c.SR.BSY == 1)               // wait bus idle

i2c.TXR = (SLAVE_ADDR_7_bit << 1) | 1 // send slave device addr
i2c.CMD.[STA, WR] = 1                 // set start and write mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')

...
i2c.CMD.RD = 1                        // set read mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')
uint32_t recv_data = i2c.RXR          // read the data
...
i2c.CMD.[STOP, RD] = 1                // set stop and read mode
while (i2c.SR.TIP == 0);              // need TIP go to 1
while (i2c.SR.TIP != 0);              // need TIP go to 0
if i2c.SR.RXK == 1: print('no receive ack')
uint32_t recv_data = i2c.RXR          // read the last data

Resoureces

References

Revision History