13-7
Seiko Epson Corporation
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
If no transmit data remains in the UART3_
n
TXD register after the stop bit has been output from the
USOUT
n
pin, the UART3_
n
INTF.TBSY bit is cleared to 0 and the UART3_
n
INTF.TENDIF bit is set to 1
(transmission completed).
Figure 13.5.2.1 Example of Data Sending Operations
Figure 13.5.2.2 Data Transmission Flowchart
Data transmission using DMA
By setting the UART3_
n
TBEDMAEN.TBEDMAEN
x
bit to 1 (DMA transfer request enabled), a DMA
transfer request is sent to the DMA controller and transmit data is transferred from the specified
memory to the UART3_
n
TXD register via DMA Ch.
x
when the UART3_
n
INTF.TBEIF bit is set to 1
(transmit buffer empty). This automates the data sending procedure described above.
The transfer source/destination and control data must be set for the DMA controller and the
relevant DMA channel must be enabled to start a DMA transfer in advance so that transmit data
will be transferred to the UART3_
n
TXD register. F
or more information on DMA, refer to the “DMA
Controller” chapte
r.
Table 13.5.2.1 DMA Data Structure Configuration Example (for Data Transmission)
Item
Setting example
End pointer
Transfer source
Memory address in which the last transmit data is stored
Transfer destination
UART3_
n
TXD register address
Control data
dst_inc
0x3 (no increment)
dst_size
0x0 (byte)
src_inc
0x0 (+1)
src_size
0x0 (byte)
R_power
0x0 (arbitrated for every transfer)
n_minus_1
Number of transfer data
cycle_ctrl
0x1 (basic transfer)
Data (W)
→
UART3_
n
TXD
Data (W)
→
UART3_
n
TXD
1 (W)
→
UART3_nINTF.TENDIF
Data (W)
→
UART3_
n
TXD
D0
D1
D2
D3
D4
D5
D6
D7
p
D0
D1
D7
p
D0
D1
D7
p
st
st
st
sp
sp
sp
(st: start bit, sp: stop bit, p: parity bit)
USOUTn
UART3_nINTF.TBEIF
UART3_nINTF.TBSY
UART3_nINTF.TENDIF
Software operations
Data transmission
Read the UART3_
n
INTF.TBEIF bit
End
Write transmit data to
the UART3_
n
TXD register
UART3_
n
INTF.TBEIF = 1 ?
Transmit data remained?
Wait for an interrupt request
(UART3_
n
INTF.TBEIF = 1)
Summary of Contents for S1C31D50
Page 461: ...25 1 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 25 Package TQFP12 48PIN ...
Page 462: ...25 2 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP13 64PIN ...
Page 463: ...25 3 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 TQFP14 80PIN ...
Page 464: ...25 4 Seiko Epson Corporation S1C31D50 TECHNICAL MANUAL Rev 1 00 QFP15 100PIN ...