Datasheet

MCP2221
DS20005292B-page 12  2015 Microchip Technology Inc.
1.4.3 GP SETTINGS MAP
The GP Settings area resides in Flash memory and is
copied into SRAM at run time. The user can alter both
the Flash and the SRAM GP settings. Any modification
in the SRAM copy of the GP settings will have an
immediate effect. The GP pins designation changes
according to the new content of the SRAM settings.
The Flash variant of the settings will affect the
Power-Up behavior of the GP pins.
TABLE 1-4: GP SETTINGS MAP
Byte
Index
Register
Name
Comments
0 GPSETTING0
GP0 pin designation and GPIO default output value, when GP is set for GPIO output operation
1 GPSETTING1 GP1 pin designation and GPIO default output value, when GP is set for GPIO output operation
2 GPSETTING2 GP2 pin designation and GPIO default output value, when GP is set for GPIO output operation
3 GPSETTING3 GP3 pin designation and GPIO default output value, when GP is set for GPIO output operation
REGISTER 1-12: GPSETTING0 REGISTER
R/W-0 R/W-0 R/W-0 R/W-1 R/W-0 R/W-0 R/W-1 R/W-0
— — — GPIOOUTVAL GPIODIR GPDES2 GPDES1 GPDES0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Reserved: Set to ‘0’
bit 4 GPIOOUTVAL: GPIO Output Value (valid only when GP0 is set for GPIO output operation)
1 = Default output value is logic ‘1’ (factory default)
0 = Default output value is logic ‘0’
bit 3 GPIODIR: GPIO Direction (input or output; valid only when GP0 is set for GPIO operation)
1 = GPIO Input
0 = GPIO Output (factory default)
bit 2-0 GPDES<2:0>: GP0 Designation
111 = Reserved
110 = Reserved
101 = Reserved
100 = Reserved
011 = Reserved
010 = Alternate function 0 (LED UART R
X – LEDURX) (factory default)
001 = Dedicated function operation (SSPND)
000 = GPIO operation (GPIO0)