r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 1109

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

20.4.5
In SSU mode, data communications are performed via four lines: clock line (SSCK), data input
line (SSI or SSO), data output line (SSI or SSO), and chip select line (SCS).
In addition, the SSU supports bidirectional mode in which a single pin functions as data input and
data output lines.
(1)
Figure 20.4 shows an example of the initial settings in SSU mode. Before data transfer, clear both
the TE and RE bits in SSER to 0 to set the initial values.
Note: Before changing operating modes and communications formats, clear both the TE and RE
[1]
[2]
[3]
[4]
[5]
Initial Settings in SSU Mode
Specify MSS, BIDE, SOL, SCKS, CSS1,
and CEIE bits in SSER smulataneously
bits to 0. Although clearing the TE bit to 0 sets the TDRE bit to 1, clearing the RE bit to 0
does not change the values of the RDRF and ORER bits and SSRDR. Those bits retain the
previous values.
Specify MLS, CPOS, CPHS, CKS2,
Specify SDOS, SSCKOS, SCSOS,
TENDSTS, SCSATS and SSODTS
Clear TE and RE bits in SSER to 0
Clear SSUMS in SSCRL to 0 and
SSU Mode
Specify TE, RE, TEIE, TIE, RIE,
specify bits DATS1 and DATS0
CKS1, and CKS0 bits in SSMR
and CSS0 bits in SSCRH
Start setting initial values
Set a bit in ICR to 1
bits in SSCR2
Figure 20.4 Example of Initial Settings in SSU Mode
End
[1] When the pin is used as an input.
[2] Specify master/slave mode selection, bidirectional mode enable,
[3] Selects SSU mode and specify transmit/receive data length.
[4] Specify MSB first/LSB first selection, clock polarity selection,
[5] Enables/disables interrupt request to the CPU.
SSO pin output value selection, SSCK pin selection, and SCS pin
selection.
clock phase selection, and transfer clock rate selection.
Section 20 Synchronous Serial Communication Unit (SSU)
Rev. 1.00 Sep. 19, 2008 Page 1079 of 1342
REJ09B0467-0100