HD6433713 datasheet(211/324 Pages) RENESAS

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Figure 11-6 8-Clock Gap Insertion (Bits GAP2 and GAP1 = 11)

11.3.4 Data Transmit/Receive

SCI2 initialization

Serial communication on SCI2 first of all requires that SCI2 be initialized by software. This

involves clearing bit STF in the status register (STSR) to 0, then selecting pin functions and

transfer modes in port mode register 2 (PMR2), port mode register 3 (PMR3), the start

address register (STAR), the end address register (EDAR), and serial control register 2

(SCR2).

Transmitting

A transmit operation is carried out as follows.

•

Set bit SO2 in port mode register 2 (PMR2) to 1, making pin P96/SO2 the SO2 output pin. If

necessary, set the SO2PMOS bit and CS bit in PMR3 for NMOS open-drain output at pin

SO2 and for chip select output at pin P95/SI2/CS.

•

Write transmit data in the 32-byte data buffer (H'FF80 to H'FF9F).

•

Set the transfer start address in the lower 5 bits of STAR.

•

Set the transfer end address in the lower 5 bits of EDAR.

•

In SCR2, select transmit mode (bit I/O = 1), the serial clock, and gap insertion (internal clock

operation only).

•

Select the data gap interval with bit GIT of STRS, then set bit STF to 1. Setting bit STF starts

the transmit operation.

SCK

output

SI input data

latch timing

Bit 14

(Bit 6)

Bit 15

(Bit 7)*

Bit 16

(Bit 8)

Note: * When bit GIT = 1, a gap is inserted at 8-bit intervals.

Serial clock

200

HD6433713 Datasheet(PDF) 211 Page - Renesas Technology Corp