HD6473847RHV Datasheet, PDF (260/546 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 9 Timers
In 8-bit mode, there are no restrictions on the order of access.
Write Access: Write access to the upper byte results in transfer of the upper-byte write data to
TEMP. Next, write access to the lower byte results in transfer of the data in TEMP to the upper
register byte, and direct transfer of the lower-byte write data to the lower register byte.
Figure 9.3 shows an example in which H'AA55 is written to TCF.
Write to upper byte
CPU
[H'AA]
Bus interface
Module data bus
TEMP
[H'AA]
Write to lower byte
CPU
[H'55]
Bus interface
TCFH
[]
TCFL
[]
Module data bus
TEMP
[H'AA]
TCFH
[H'AA]
TCFL
[H'55]
Figure 9.3 Write Access to TCF (CPU → TCF)
Read Access: In access to TCF, when the upper byte is read the upper-byte data is transferred
directly to the CPU and the lower-byte data is transferred to TEMP. Next, when the lower byte is
read, the lower-byte data in TEMP is transferred to the CPU.
In access to OCRF, when the upper byte is read the upper-byte data is transferred directly to the
CPU. When the lower byte is read, the lower-byte data is transferred directly to the CPU.
Figure 9.4 shows an example in which TCF is read when it contains H'AAFF.
Rev. 7.00 Mar. 08, 2010 Page 228 of 510
REJ09B0024-0700