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TMP89FM42
RA001
13.4.1.4 Register buffer configuration
(1)
Temporary buffer
The TMP89FM42 contains an 8-bit temporary buffer. When a write instruction is executed on
TA0DRAL, the data is first stored into this temporary buffer, whether the double buffer is enabled or
disabled. Subsequently, when a write instruction is executed on TA0DRAH, the set value is stored
into the double buffer or TA0DRAH. At the same time, the set value in the temporary buffer is stored
into the double buffer or TA0DRAL. (This structure is designed to enable the set values of the lower-
level and higher-level registers simultaneously.) Therefore, when setting data to TA0DRA, be sure to
write the data into TA0DRAL and TA0DRAH in this order.
See Figure 13-1 for the temporary buffer configuration.
(2)
Double buffer
In the TMP89FM42, the double buffer can be used by setting TA0CR<TA0DBF>. Setting
TA0CR<TA0DBF> to "0" disables the double buffer. Setting TA0CR<TA0DBF> to "1" enables the
double buffer.
See Figure 13-1 for the double buffer configuration.
- When the double buffer is enabled
When a write instruction is executed on TA0DRAH during the timer operation, the set
value is first stored into the double buffer, and TA0DRAH/L are not updated immediately.
TA0DRAH/L compare the up counter value to the last set values. If the values are matched,
an INTTCA0 interrupt request is generated and the double buffer set value is stored in
TA0DRAH/L. Subsequently, the match detection is executed using a new set value.
When a read instruction is executed on TA0DRAH/L, the double buffer value (the last set
value) is read, rather than the TA0DRAH/L values (the current effective values).
When a write instruction is executed on TA0DRAH/L while the timer is stopped, the set
value is immediately stored into both the double buffer and TA0DRAH/L.
- When the double buffer is disabled
When a write instruction is executed on TA0DRAH during the timer operation, the set
value is immediately stored into TA0DRAH/L. Subsequently, the match detection is exe-
cuted using a new set value.
If the values set to TA0DRAH/L are smaller than the up counter value, the match detection
is executed using a new set value after the up counter overflows. Therefore, the interrupt
request interval may be longer than the selected time. If that is a problem, enable the double
buffer.
When a write instruction is executed on TA0DRAH/L while the timer is stopped, the set
value is immediately stored into TA0DRAH/L.
Summary of Contents for TLCS-870/C1 Series
Page 1: ...8 Bit Microcontroller TLCS 870 C1 Series TMP89FM42 查询TMP89FM42供应商 捷多邦 专业PCB打样工厂 24小时加急出货 ...
Page 3: ...Revision History Date Revision 2007 10 25 1 First Release 2007 11 3 2 Contents Revised ...
Page 4: ......
Page 14: ......
Page 18: ...1 3 Block Diagram TMP89FM42 1 3 Block Diagram Figure 1 2 Block Diagram ...
Page 22: ...1 4 Pin Names and Functions TMP89FM42 ...
Page 60: ...2 CPU Core 2 5 Revision History TMP89FM42 ...
Page 76: ...3 Interrupt Control Circuit 3 8 Revision History TMP89FM42 ...
Page 86: ...4 External Interrupt control circuit 4 3 Function TMP89FM42 ...
Page 102: ...7 Voltage Detection Circuit 7 5 Revision History TMP89FM42 ...
Page 126: ...8 I O Ports 8 3 I O Port Registers TMP89FM42 Note 2 i 0 to 1 ...
Page 136: ...8 I O Ports 8 5 Revision History TMP89FM42 ...
Page 142: ...9 Special Function Registers 9 3 SFR3 0x0E40 to 0x0EFF TMP89FM42 ...
Page 146: ...10 Low Power Consumption Function for Peripherals TMP89FM42 ...
Page 149: ...TMP89FM42 11 3 Revision History Rev Description RA001 Deleted SLEEP2 description ...
Page 150: ...11 Divider Output DVO 11 3 Revision History TMP89FM42 ...
Page 220: ...15 Real Time Clock RTC 15 4 Real Time Clock Operation TMP89FM42 ...
Page 250: ...16 Asynchronous Serial Interface UART 16 15 Revision History TMP89FM42 ...
Page 302: ...18 Serial Bus Interface SBI 18 7 Revision History TMP89FM42 ...
Page 338: ...21 Flash Memory 21 4 Toggle Bit D6 TMP89FM42 ...
Page 384: ...22 Serial PROM Mode 22 15 Revision History TMP89FM42 ...
Page 388: ...24 Input Output Circuit 24 1 Control Pins TMP89FM42 ...
Page 404: ...25 Electrical Characteristics 25 11 Revision History TMP89FM42 ...
Page 406: ...26 Package Dimensions TMP89FM42 ...
Page 408: ......