User Manual

Apollo3 Blue Datasheet
DS-A3-0p9p1 Page 421 of 909 2019 Ambiq Micro, Inc.
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15:14 PAD5RSEL 0x0 RW
Pad 5 pullup resistor selection.
PULL1_5K = 0x0 - Pullup is ~1.5 KOhms
PULL6K = 0x1 - Pullup is ~6 KOhms
PULL12K = 0x2 - Pullup is ~12 KOhms
PULL24K = 0x3 - Pullup is ~24 KOhms
13:11 PAD5FNCSEL 0x3 RW
Pad 5 function select
M0SCL = 0x0 - Configure as the IOMSTR0 I2C SCL signal
M0SCK = 0x1 - Configure as the IOMSTR0 SPI SCK signal
UA0RTS = 0x2 - Configure as the UART0 RTS signal output
GPIO5 = 0x3 - Configure as GPIO5
RSVD4 = 0x4 - Reserved
RSVD6 = 0x6 - Reserved
CT8 = 0x7 - CTIMER connection 8
10 PAD5STRNG 0x0 RW
Pad 5 drive strength
LOW = 0x0 - Low drive strength
HIGH = 0x1 - High drive strength
9 PAD5INPEN 0x0 RW
Pad 5 input enable
DIS = 0x0 - Pad input disabled
EN = 0x1 - Pad input enabled
8PAD5PULL 0x0RW
Pad 5 pullup enable
DIS = 0x0 - Pullup disabled
EN = 0x1 - Pullup enabled
7:6 RSVD 0x0 RO
RESERVED
5:3 PAD4FNCSEL 0x3 RW
Pad 4 function select
UA0CTS = 0x0 - Configure as the UART0 CTS input signal
SLINT = 0x1 - Configure as the IOSLAVE interrupt out signal
NCE4 = 0x2 - IOM/SPI nCE group 4
GPIO4 = 0x3 - Configure as GPIO4
RSVD4 = 0x4 - Reserved
UART0RX = 0x5 - Configure as the UART0 RX input
CT17 = 0x6 - CTIMER connection 17
MSPI2 = 0x7 - MSPI data connection 2
2 PAD4STRNG 0x0 RW
Pad 4 drive strength
LOW = 0x0 - Low drive strength
HIGH = 0x1 - High drive strength
1 PAD4INPEN 0x0 RW
Pad 4 input enable
DIS = 0x0 - Pad input disabled
EN = 0x1 - Pad input enabled
0PAD4PULL 0x0RW
Pad 4 pullup enable
DIS = 0x0 - Pullup disabled
EN = 0x1 - Pullup enabled
Table 628: PADREGB Register Bits
Bit Name Reset RW Description