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9-9 ___________________________________________________________________________________________________________

MAXQ7667 User’s Guide

9.1.1.3 SPI Configuration Register (SPICF)

The SPI configuration register (SPICF) contains the port configuration selects. The SPI port supports 8-bit and 16-bit character trans-

fers using the SS pin and an internal bit counter to control transfer completion. Data is shifted on the rising or falling edge of the SCLK

as selected by the clock polarity select (CKPOL) and the clock phase select (CKPHA) bits found in the SPICF. These registers can be

word, byte, or bit accessed.

Table 9-2 shows the four SPI clocking modes supported by the MAXQ7667.

Table 9-2. SPI Clocking Mode Configuration

Bits 15 to 8, 5 to 3: Reserved.

Read 0, write ignored.

Bit 7: Enable SPI Interrupt (ESPII). This bit enables any of the SPI interrupt source flags (MODF, WCOL, ROVR, SPIC) to generate

interrupt requests.

0 = SPI interrupt sources disabled.

1 = SPI interrupt sources enabled.

Bit 6: Slave-Active Select (SAS). This bit is used to determine the SS active state. When the SAS is cleared to 0, the SS is active low

and responds to an external low signal. When the SAS is set to 1, the SS pin is active high. Note: The SAS selection is only available

in the enhanced SPI peripheral.

Bit 2: Character Length Select (CHR). This bit determines the character length for an SPI transfer cycle. A character can be 8 bits in

length or 16 bits in length.

0 = 8-bit character length specified.

1 = 16-bit character length specified.

SPI

MODE

CLOCK

POLARITY

(CKPOL)

CLOCK

PHASE

(CKPHA)

TRANSFER METHOD

0 0 0 SPICK rising edge transfer

1 0 1 SPICK falling edge transfer

2 1 0 SPICK falling edge transfer

3 1 1 SPICK rising edge transfer

Bit #

15 14 13 12 11 10 98

Name — — — — — — — —

Reset 0 0 0 0 0 0 0 0

Access r r r r r r r r

Bit #

76543210

Name ESPII SAS — — — CHR CKPHA CKPOL

Reset 0 0 0 0 0 0 0 0

Access rw rw r r r rw rw rw

r = read, w = write

1 2 ... 166 167 168 169 170 171 172 173 174 175 176 ... 346 347

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