HD6432621 Hitachi, HD6432621 Datasheet - Page 513

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Serial data transmission (clocked synchronous mode)
Figure 13-16 shows a sample flowchart for serial transmission.
The following procedure should be used for serial data transmission.
Write transmit data to TDR and
clear TDRE flag in SSR to 0
Clear TE bit in SCR to 0
Read TDRE flag in SSR
Read TEND flag in SSR
All data transmitted?
Start transmission
Initialization
TDRE= 1
TEND= 1
<End>
Figure 13-16 Sample Serial Transmission Flowchart
Yes
Yes
Yes
No
No
No
[3]
[2]
[1]
[1] SCI initialization:
[2] SCI status check and transmit data
[3] Serial transmission continuation
The TxD pin is automatically
designated as the transmit data output
pin.
write:
Read SSR and check that the TDRE
flag is set to 1, then write transmit data
to TDR and clear the TDRE flag to 0.
procedure:
To continue serial transmission, be
sure to read 1 from the TDRE flag to
confirm that writing is possible, then
write data to TDR, and then clear the
TDRE flag to 0.
Checking and clearing of the TDRE
flag is automatic when the DTC is
activated by a transmit data empty
interrupt (TXI) request and data is
written to TDR.
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