EM78P311SXSSLASHXJ datasheet(37/68 Pages) EMC

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EM78P311N

8-Bit Microcontroller

Product Specification (V1.0) 10.02.2006

• 33

(This specification is subject to change without further notice)

(b)

8-bit Receive Mode:

Setting SPIM0 ~ SPIM1 to receive mode and setting SPIS to “1” to start receiving.

The data are input sequentially from the SI pin in synchronous with the serial

clock. When the final bit of transfer data has been received, the SPI interrupt is

generated and SPIS is cleared to “0” by hardware. In order to receive the next

data, the SPIS must be set to “1” again by software. If the current data is not read

out from the data buffer, receiving is not started when using internal clock.

/SCK pin

RBF

WBE

SPIF

read data

shift start

SI pin

a0 a1 a2 a3 a4 a5 a6 a7

SPID

b0 b1 b2 b3 b4 b5 b6 b7

read data

shift finish

Fig. 5-15 Receive Mode (8-bit, 1 word)

Set SPIM0 ~ SPIM1 to transmit/receive mode and write data to data buffer SPID.

Set SPIS to “1” to start transferring. The data are output to the SO pin and input

from the SI pin sequentially in synchronous with the serial clock. When the

number of data words specified has been transferred, the SPI interrupt is

generated and SPIS is cleared to “0” by hardware. In order to receive the next

data, the SPIS must be set to “1” again by software. Writing data in transmit

mode and reading data in receive mode use the same data buffer. If the current

data is not read out from the data buffer and then write the data to data buffer, the

transfer is not started when using internal clock. Always write the data to be

transmitted after reading the received data.

EM78P311SXS/XJ Datasheet(PDF) 37 Page - ELAN Microelectronics Corp