Datasheet
Section 22 Synchronous Serial Communication Unit (SSU)
REJ09B0465-0300 Rev. 3.00 Page 775 of 982
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
Bit Symbol Bit Name Description R/W
0 SSUMS SSU mode
select
0: Clocked synchronous communication mode
Data input: SSI pin, Data output: SSO pin
1: Four-line bus communication mode
When MSS = 1 in SSCRH and BIDE = 0 in
SSMR2:
Data input: SSI pin, Data output: SSO pin
When MSS = 0 in SSCRH and BIDE = 0 in
SSMR2:
Data input: SSO pin, Data output: SSI pin
When BIDE = 1 in SSMR2:
Data input and output: SSO pin
R/W
[Legend]
X: Don't care.
Notes: 1. To function these pins as ports, clear the PMR bit corresponding to the pin to 0.
2. If the NMOS open-drain output is selected, use the PMC to allocate the pin from port
5. If the pin is allocated from a port other than port 5, only the CMOS output can be
selected.
3. When the functions of SSI output and SCS output are allocated to P57 and P56,
respectively, the output with this setting is NMOS push-pull. This differs from the
CMOS output in its high-level output characteristics. On the other hand, if these
functions are allocated to other pins, the output with this setting is CMOS.
• BIDE bit (bidirectional mode enable)
Selects whether the serial data input pin and the output pin are both used or only one pin is
used. For details, see section 22.3.3, Relationship between Data Input/Output Pin and Shift
Register. When the SSUMS bit in SSMR2 is 0, this setting is invalid.
• SCKS bit (SSCK pin select)
Selects whether the SSCK pin functions as a port or a serial clock pin.
• CSS[1:0] bits (SCS pin select)
Selects whether the SCS pin functions as a port, an SCS input, or SCS output. When the
SSUMS bit in SSMR2 is 0, the SCS pin functions as a port regardless of the setting of this bit.