User Manual

Apollo3 Blue Datasheet
DS-A3-0p9p1 Page 433 of 909 2019 Ambiq Micro, Inc.
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21:19 PAD26FNCSEL 0x3 RW
Pad 26 function select
NCE26 = 0x1 - IOM/MSPI nCE group 26
CT3 = 0x2 - CTIMER connection 3
GPIO26 = 0x3 - Configure as GPIO26
SCCRST = 0x4 - SCARD reset output
MSPI1 = 0x5 - MSPI data connection 1
UART0TX = 0x6 - Configure as UART0 TX output signal
UA1CTS = 0x7 - Configure as UART1 CTS input signal
18 PAD26STRNG 0x0 RW
Pad 26 drive strength
LOW = 0x0 - Low drive strength
HIGH = 0x1 - High drive strength
17 PAD26INPEN 0x0 RW
Pad 26 input enable
DIS = 0x0 - Pad input disabled
EN = 0x1 - Pad input enabled
16 PAD26PULL 0x0 RW
Pad 26 pullup enable
DIS = 0x0 - Pullup disabled
EN = 0x1 - Pullup enabled
15:14 PAD25RSEL 0x0 RW
Pad 25 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 PAD25FNCSEL 0x3 RW
Pad 25 function select
UART1RX = 0x0 - Configure as UART1 RX input signal
NCE25 = 0x1 - IOM/MSPI nCE group 25
CT1 = 0x2 - CTIMER connection 1
GPIO25 = 0x3 - Configure as GPIO25
M2SDAWIR3 = 0x4 - Configure as the IOMSTR2 I2C SDA or SPI WIR3 sig-
nal
M2MISO = 0x5 - Configure as the IOMSTR2 SPI MISO input signal
RSVD6 = 0x6 - Reserved
RSVD7 = 0x7 - Reserved
10 PAD25STRNG 0x0 RW
Pad 25 drive strength
LOW = 0x0 - Low drive strength
HIGH = 0x1 - High drive strength
9 PAD25INPEN 0x0 RW
Pad 25 input enable
DIS = 0x0 - Pad input disabled
EN = 0x1 - Pad input enabled
8 PAD25PULL 0x0 RW
Pad 25 pullup enable
DIS = 0x0 - Pullup disabled
EN = 0x1 - Pullup enabled
7:6 RSVD 0x0 RO
RESERVED
Table 638: PADREGG Register Bits
Bit Name Reset RW Description