ISD91200 Series Technical Reference Manual
Release Date: Sep 16, 2019
- 39 -
Revision 2.4
GPIO Alternative Function Control Register (SYS_GPA_MFP, SYS_GPB_MFP)
Each GPIO pin can take on multiple alternate functions depending on the setting of this register. Each
pin has two bits of alternate function control. Set to 00 the pin is a standard GPIO pin whose attributes
are defined by the GPIO control registers (See Section 0). Set to other values the pin is assigned to a
peripheral as outlined in table below.
Register
Offset
R/W
Description
Reset Value
SYS_GPA_MFP
0x38
R/W
GPIOA multiple alternate functions control register
0x0000_0000
31
30
29
28
27
26
25
24
PA15MFP
PA14MFP
PA13MFP
PA12MFP
23
22
21
20
19
18
17
16
PA11MFP
PA10MFP
PA9MFP
PA8MFP
15
14
13
12
11
10
9
8
PA7MFP
PA6MFP
PA5MFP
PA4MFP
7
6
5
4
3
2
1
0
PA3MFP
PA2MFP
PA1MFP
PA0MFP
Table 5-7 GPIOA Alternate Function Register (SYS_GPA_MFP address 0x5000_0038)
Bits
Description
[31:30]
PA15MFP
Alternate Function Setting for PA15MFP
00 = GPIO.
01 = UART1_RX.
10 = MCLK.
11 = X32KO.
[29:28]
PA14MFP
Alternate Function Setting for PA14MFP
00 = GPIO.
01 = UART1_TX.
10 = DMIC_CLK.
11 = X32KI.
[27:26]
PA13MFP
Alternate Function Setting for PA13MFP
00 = GPIO.
01 = PWM0CH3.
10 = X12MO.
11 = I2C0_SCL.
[25:24]
PA12MFP
Alternate Function Setting for PA12MFP
00 = GPIO.
01 = PWM0CH2.
10 = X12MI.
11 = I2C0_SDA.