HD6432621 Hitachi, HD6432621 Datasheet - Page 506

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

In serial transmission, the SCI operates as described below.
[1] The SCI monitors the TDRE flag in SSR, and if is 0, recognizes that data has been written to
[2] After transferring data from TDR to TSR, the SCI sets the TDRE flag to 1 and starts
[3] The SCI checks the TDRE flag at the timing for sending the stop bit.
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TDR, and transfers the data from TDR to TSR.
transmission.
If the TIE bit in SCR is set to 1 at this time, a transmit data empty interrupt (TXI) is generated.
The serial transmit data is sent from the TxD pin in the following order.
[a] Start bit:
[b] Transmit data:
[c] Multiprocessor bit
[d] Stop bit(s):
[e] Mark state:
If the TDRE flag is cleared to 0, data is transferred from TDR to TSR, the stop bit is sent, and
then serial transmission of the next frame is started.
If the TDRE flag is set to 1, the TEND flag in SSR is set to 1, the stop bit is sent, and then the
mark state is entered in which 1 is output continuously. If the TEIE bit in SCR is set to 1 at this
time, a transmission end interrupt (TEI) request is generated.
One 0-bit is output.
8-bit or 7-bit data is output in LSB-first order.
One multiprocessor bit (MPBT value) is output.
One or two 1-bits (stop bits) are output.
1 is output continuously until the start bit that starts the next transmission is sent.