HD64F3644PV Datasheet, PDF (309/551 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 10 Serial Communication Interface
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 _SCK1
Group _SO1
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.
SCK₁
SO₁
Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 14 Bit 15
1 frame
TAIL MARK
Figure 10.4 Transfer Format (When SNC1 = 0, SNC0 = 1, MRKON = 1)
Rev. 6.00 Sep 12, 2006 page 287 of 526
REJ09B0326-0600