371
CHAPTER 20 UART2, UART3
20.5.2
Transmission Interrupt Generation and Flag Set Timing
A transmission interrupt is generated when the transmission data is transferred from
transmission data register (TDR2/TDR3) to transmission shift register and started.
■
Transmission Interrupt Generation and Flag Set Timing
A transmission interrupt is generated, when the next data to be sent is ready to be written to the
Transmission Data Register (TDR2/TDR3), i. e. the TDR2/TDR3 is empty, and the transmission interrupt
is enabled by setting the Transmission Interrupt Enable (TIE) bit of the Serial Status Register (SSR2/SSR3)
to "1".
The Transmission Data Register Empty (TDRE) flag bit of the SSR2/SSR3 indicates an empty TDR2/
TDR3. Because the TDRE bit is "read only", it only can be cleared by writing data into TDR2/TDR3.
The following figure demonstrates the transmission operation and flag set timing for the four modes of
UART2, UART3.
Figure 20.5-3 Transmission Operation and Flag Set Timing
Note:
The example in Figure 20.5-3 does not show all possible transmission options for mode 0. Here it is:
"8p1" (p = "E" [even] or "O" [odd]). Parity is not provided in mode 3 or 2, if SSM = 0.
Mode 0, 1, 2 (
SS
M=1) or
3
:
TDRE
s
eri
a
l o
u
tp
u
t
Mode 2 (
SS
M = 0):
TDRE
s
eri
a
l o
u
tp
u
t
tr
a
n
s
mi
ss
ion interr
u
pt occ
u
r
s
tr
a
n
s
mi
ss
ion interr
u
pt occ
u
r
s
D0 D1 D2 D
3
D4 D5 D6 D7 D0 D1 D2 D
3
D4 D5 D6 D7 D0 D1 D2 D
3
D4
S
T D0 D1 D2 D
3
D4 D5 D6 D7
S
P
S
T D0 D1 D2 D
3
D4 D5 D6 D7
S
P
P
AD
P
AD
tr
a
n
s
mi
ss
ion interr
u
pt occ
u
r
s
tr
a
n
s
mi
ss
ion interr
u
pt occ
u
r
s
S
T:
S
t
a
rt
b
it D0 ... D7: d
a
t
a
b
it
s
P: P
a
rity
S
P:
S
top
b
it AD: Addre
ss
/d
a
t
a
s
election
b
it (mode1)
write to TDR2/TDR
3
write to TDR2/TDR
3
Содержание MB90390 Series
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Страница 4: ......
Страница 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
Страница 18: ...xiv ...
Страница 132: ...104 CHAPTER 5 CLOCKS ...
Страница 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Страница 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Страница 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Страница 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Страница 274: ...246 CHAPTER 15 WATCH TIMER ...
Страница 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Страница 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Страница 364: ...336 CHAPTER 19 UART0 UART1 ...
Страница 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Страница 432: ...404 CHAPTER 20 UART2 UART3 ...
Страница 482: ...454 CHAPTER 22 SERIAL I O ...
Страница 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Страница 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Страница 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Страница 722: ...694 APPENDIX ...
Страница 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
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