HD6433644R datasheet(307/549 Pages) RENESAS

307 / 549 page

Section 10 Serial Communication Interface

Rev. 6.00 Sep 12, 2006 page 287 of 526

REJ09B0326-0600

10.2.4

Operation in SSB Mode

SSB communication uses two lines, SCL (Serial Clock) and SDA (Serial Data), and enables

multiple ICs to be connected as shown in figure 10.3.

In SSB mode, TAIL MARK is sent after an 8- or 16-bit data transfer. HOLD TAIL or LATCH

TAIL can be selected as TAIL MARK.

H8/3644

Group

SCK

SCL

SDA

IC-A

IC-B

IC-C

Figure 10.3 Example of SSB Connection

Clock: The transfer clock can be selected from eight internal clocks or an external clock, but since

the H8/3644 Group uses clock output, an external clock should not be selected. The transfer rate

can be selected by bits CKS2 to CKS0 in SCR1. Since this is also the TAIL MARK transfer rate,

the setting should be made to give a transfer clock cycle of at least 2 µs.

Data Transfer Format: Figure 10.4 shows the SCI1 transfer format. Data is sent starting from the

least significant bit, in LSB-first format. TAIL MARK is sent after an 8- or 16-bit data transfer.

SCK

Bit 1

Bit 0

Bit 2

Bit 3

Bit 4

Bit 14

Bit 5

Bit 15

TAIL MARK

1 frame

Figure 10.4 Transfer Format (When SNC1 = 0, SNC0 = 1, MRKON = 1)

HD6433644R Datasheet(PDF) 307 Page - Renesas Technology Corp