User Manual

Apollo3 Blue Datasheet
DS-A3-0p9p1 Page 394 of 909 2019 Ambiq Micro, Inc.
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A variety of pads may be used for up to four nCE signals to select up to four separate slaves. The nCE
signals are pre-muxed into a signal group called NCE. The muxing configuration is shown in Table 564.
The PADnINPEN and PADnPULL bits of any pad used for nCE should be cleared.
11.5.1.14IO Master 1 3-wire SPI Connection
Three-wire SPI mode of IO Master 1 uses pad 8 as SCK and pad 9 as MOSI/MISO. This mode is
configured by setting the PADnFNCSEL fields as shown in Table 579. The PAD8INPEN and PAD9INPEN
bits must be set. PAD8PULL and PAD9PULL should be cleared. Pad 10 may be used for other functions.
A variety of pads may be used for up to four nCE signals to select up to four separate slaves. The nCE
signals are pre-muxed into a signal group called NCE. The muxing configuration is shown in Table 564.
The PADnINPEN and PADnPULL bits of any pad used for nCE should be cleared.
11.5.1.15IO Master 2 3-wire SPI Connection
Three-wire SPI mode of IO Master 2 uses pad 27 as SCK and pad 25 as MOSI/MISO. This mode is
configured by setting the PADnFNCSEL fields as shown in Table 580. The PAD27INPEN and
PAD25INPEN bits must be set. PAD27PULL and PAD25PULL should be cleared. Pad 28 may be used for
other functions.
A variety of pads may be used for up to four nCE signals to select up to four separate slaves. The nCE
signals are pre-muxed into a signal group called NCE. The muxing configuration is shown in Table 564.
The PADnINPEN and PADnPULL bits of any pad used for nCE should be cleared.
11.5.1.16IO Master 3 3-wire SPI Connection
Three-wire SPI mode of IO Master 3 uses pad 42 as SCK and pad 43as MOSI/MISO. This mode is
configured by setting the PADnFNCSEL fields as shown in Table 581. The PAD42INPENand
PAD43INPENbits must be set. PAD42PULL and PAD43PULLshould be cleared. Pad 38 may be used for
other functions.
Table 579: IO
Master 1 3-wire SPI Configuration
Field Value
PAD8FNCSEL 1
PAD9FNCSEL 0
Table 580: IO Master 2 3-wire SPI Configuration
Field Value
PAD27FNCSEL 5
PAD25FNCSEL 4
Table 581: IO Master 3 3-wire SPI Configuration
Field Value
PAD42FNCSEL 5
PAD43FNCSEL 4