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Z380

™

USER'S MANUAL

ZILOG

DC-8297-03

OTIM

OUTPUT INCREMENT MEMORY

OTIM

Operation: (C) ← (HL)

C ← C + 1

B ← B – 1

HL ← HL + 1

This instruction is used for block output of strings of data to on-chip peripherals. No external

I/O transaction will be generated as a result of this instruction, although the I/O address will

appear on the address bus and the write data will appear on the data bus while this internal

write is occurring. The peripheral address is placed on the low byte of the address bus and

zeros are placed on all other address lines. The byte of data from the memory location

addressed by the HL register is loaded to the on-chip I/O port addressed by the C register.

The C register, holding the port address, is incremented by one to select the next output port.

The B register, used as a counter, is then decremented by one. The HL register is then

incremented by one, thus moving the pointer to the next source for the output.

Flags: S: Set if the result of decrementing B is negative; cleared otherwise

Z: Set if the result of decrementing B is zero; cleared otherwise

H: Set if there is a borrow from bit 4 during the decrement of the B register; cleared

otherwise

P: Set if the result of the decrement of the B register is even; cleared otherwise

N: Set if the most significant bit of the byte transferred was a 1; cleared otherwise

C: Set if there is a borrow from the most significant bit during the decrement of the B

Addressing Execute

Mode Syntax Instruction Format Time Note

OTIM 11101101 10000011 2+r+o

1 2 ... 146 147 148 149 150 151 152 153 154 155 156 ... 267 268

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