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Bits 7 to 4—Instruction Address (IA15 to IA12): These bits specify the high-order four bits
(bits 15 to 12) of the address pointing to the area storing the write instruction for reloading the
TCNT value. When specifying the IA15 to IA12 bits, set the WAD bit to 0 at the same time. For
example, when H'X is specified in the IA15 to IA12 bits, the write instruction for reloading TCNT
must be placed in the 4-kbyte area ranging from address H'X000 to address H'XFF7 in the ROM
area; a write instruction placed outside the area cannot reload TCNT. Any value can be specified
as an operand (write data) of the write instruction for reloading TCNT; the initially written value is
always reloaded to TCNT.
Bits 3 to 1—Reserved: Always read as 1 and cannot be written to.
Bit 0—Write Address Disable (WAD): Enables or disables TCWA. When WAD = 1, TCWA
does not operate. When writing data to IA15 to IA12 in TCWA, set the WAD bit to 0 at the same
time; the TCWA data becomes valid only after TCWA is written to. If 1 is written to the WAD bit
at the same time as a write address is written to IA15 to IA12, the write address becomes invalid.
The TCWA data can always be read regardless of the WAD bit setting.
Bit 0: WAD
Description
0
TCWA operates. The TCWA data is valid.
1
TCWA does not operate. The TCWA data is invalid.
(Initial value)