List the control and status signal of 8085 microprocessor and mention its need?
2 years ago
Microprocessors
ALE (Output):
- Address Latch Enable: It occurs during the first clock cycle of a machine state and enables the address to get latched into the on chip latch of peripherals.
- The falling edge of ALE is set to guarantee set up and hold times for the address information. ALE can also be used to store the status information.
RD(Output3state):
- READ: indicates the selected memory or I/0 device is to be read and that the Data Bus is available for the data transfer.
WR (Output3state):
- WRITE: indicates the data on the Data Bus is to be written into the selected memory or I/0 location. Data is set up at the trailing edge of WR. 3stated during Hold and Halt modes.
IO/M,S0,S1:
- IO/M indicates whether input output operation or memory operation is being carried out.
- S0 and S1 indicated the type os machine cycle in progress.
READY(Input):
- If Ready is high during a read or write cycle, it indicates that the memory or peripheral is ready to send or receive data .
- If Ready is low, the CPU will wait for Ready to go high before completing the read or write cycle.
Rusma Khadka
Sep 9, 2022