h8s-2635 Renesas Electronics Corporation., h8s-2635 Datasheet - Page 741

• Manufacturer Part Number: h8s-2635
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 17 A/D Converter
17.3
Interface to Bus Master
ADDRA to ADDRD are 16-bit registers, and the data bus to the bus master is 8 bits wide.
Therefore, in accesses by the bus master, the upper byte is accessed directly, but the lower byte is
accessed via a temporary register (TEMP).
A data read from ADDR is performed as follows. When the upper byte is read, the upper byte
value is transferred to the CPU and the lower byte value is transferred to TEMP. Next, when the
lower byte is read, the TEMP contents are transferred to the CPU.
When reading ADDR, always read the upper byte before the lower byte. It is possible to read only
the upper byte, but if only the lower byte is read, incorrect data may be obtained.
Figure 17-2 shows the data flow for ADDR access.
Figure 17-2 ADDR Access Operation (Reading H'AA40)
Rev. 6.00 Feb 22, 2005 page 681 of 1484
REJ09B0103-0600