M38005M2DXXXFP View Datasheet(PDF) - MITSUBISHI ELECTRIC

Part Name

Description

Manufacturer

M38005M2DXXXFP

8-BIT SINGLE-CHIP MICROCOMPUTER

MITSUBISHI ELECTRIC  

APPLICATION

2.3 Serial I/O

Control procedure :

Control in the master unit

After a setting of the related registers is completed as shown in Figure 2.3.33, in the master unit

transmission or reception of 1-byte data is started simply by writing transmission data to the

Transmit buffer register.

To perform the communication in the timing shown in Figure 2.3.25, therefore, take the timing into

account and write transmission data. Read out the reception data when the Serial I/O transmit

interrupt request bit is set to “1,” or before the next transmission data is written to the Transmit

buffer register.

A processing example in the master unit using timer interrupts is shown below.

Interrupt processing routine

executed every 488 µs

CLT (Note 1)

CLD (Note 2)

Push register to stack

Note 1: When using the Index X mode flag (T).

Note 2: When using the Decimal mode flag (D).

q Push the register used in the interrupt

processing routine into the stack.

N

Within a block transfer period?

Y

Read a reception data

q Generate a certain block interval by

using a timer or other functions.

Count a block interval counter

q Check the block interval counter and

determine to start of a block transfer.

Y

Complete to transfer a block?

N

Write a transmission data

N

Start a block transfer?

Y

Write the first transmission data

(first byte) in a block

Pop registers

q Pop registers which is pushed to stack.

RTI

Fig. 2.3.27 Control in the master unit

3800 GROUP USER’S MANUAL

2-41

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