BH66F2260 Datasheet, PDF (85/214 Pages) Holtek Semiconductor Inc – R-Sensor Blood Pressure Meter Flash MCU

BH66F2260
R-Sensor Blood Pressure Meter Flash MCU
PTMn
PTCKn
CCR capture input
PTPnI
CCR output
PTPn
PTPnB
Note: Only the PTM0 has the inverted output pin PTP0B.
PTM Function Pin Control Block Diagram (n=0~2)
Programming Considerations
The TM Counter Registers and the Capture/Compare CCRA and CCRP registers, all have a low and
high byte structure. The high bytes can be directly accessed, but as the low bytes can only be accessed
via an internal 8-bit buffer, reading or writing to these register pairs must be carried out in a specific
way. The important point to note is that data transfer to and from the 8-bit buffer and its related low
byte only takes place when a write or read operation to its corresponding high byte is executed.
As the CCRA and CCRP registers are implemented in the way shown in the following diagram and
accessing these register pairs is carried out in a specific way as described above, it is recommended
to use the "MOV" instruction to access the CCRA and CCRP low byte registers, named xTMnAL
and PTMnRPL, using the following access procedures. Accessing the CCRA or CCRP low byte
registers without following these access procedures will result in unpredictable values.
xTMn Counter Register (Read only)
xTMnDL xTMnDH
8-bit Buffer
xTMnAL xTMnAH
xTMn CCRA Register (Read/Write)
PTMnRPL PTMnRPH
PTMn CCRP Register (Read/Write)
Data Bus
The following steps show the read and write procedures:
• Writing Data to CCRA
♦♦ Step 1. Write data to Low Byte xTMnAL or PTMnRPL
––Note that here data is only written to the 8-bit buffer.
♦♦ Step 2. Write data to High Byte xTMnAH or PTMnRPH
––Here data is written directly to the high byte registers and simultaneously data is latched
from the 8-bit buffer to the Low Byte registers.
• Reading Data from the Counter Registers and or CCRA
♦♦ Step 1. Read data from the High Byte xTMnDH, xTMnAH or PTMnRPH
––Here data is read directly from the High Byte registers and simultaneously data is latched
from the Low Byte register into the 8-bit buffer.
♦♦ Step 2. Read data from the Low Byte xTMnDL, xTMnAL or PTMnRPL
––This step reads data from the 8-bit buffer.
Rev. 1.00
85
March 15, 2017