RTL8231 GPIO expander

The RTL8231 IC is a companion chip often used with RTL83xx SoCs to extend the number of available GPIOs or LED outputs. It can be controlled via SMI (I2C-like), MIIM, or as a shift register. It comes in an LQFP-48 package:

    |36      25| 
  - +----------+ -
 37 |          | 24
    | RTL8231  |
 48 | o        | 13
  - +----------+ -
    |1       12|
Number Name Description
15 SMI_DIS Disable SMI/MIIM mode and run in shift-register mode if pulled high.
42 MOD[0] SMI/MIIM mode: pull high to run in MIIM mode, pull low for SMI (I2C) mode.
37 ADDR[0] MIIM mode: ADDR[4:0] indicates the device address
SMI mode: ADDR[2:0] indicates the three lowest bits of the device address. If ADDR[3] is pulled low, 8-bit register addresses are used, if it is pulled high 16-bit wide registers addresses are used.
38 ADDR[1]
39 ADDR[2]
40 ADDR[3]
41 ADDR[4]
  • rtl8231.txt
  • Last modified: 2021/11/19 22:24
  • by svanheule