Holtek BS66F340 - Look-Up Table Registers - TBLP, TBHP, TBLH; Status Register - STATUS

Rev. 1.60 60 August 20, 2019 Rev. 1.60 61 August 20, 2019
BS66F340/BS66F350/BS66F360/BS66F370
Touch A/D Flash MCU with LED Driver
BS66F340/BS66F350/BS66F360/BS66F370
Touch A/D Flash MCU with LED Driver
Look-up Table Registers – TBLP, TBHP, TBLH
These three special function registers are used to control operation of the look-up table which is
stored in the Program Memory. TBLP and TBHP are the table pointer and indicates the location
where the table data is located. Their value must be setup before any table read commands are
executed. Their value can be changed, for example using the "INC" or "DEC" instructions, allowing
for easy table data pointing and reading. TBLH is the location where the high order byte of the table
data is stored after a table read data instruction has been executed. Note that the lower order table
data byte is transferred to a user dened location.
Status Register – STATUS
This 8-bit register contains the zero ag (Z), carry ag (C), auxiliary carry ag (AC), overow ag
(OV), SC ag, CZ ag, power down ag (PDF), and watchdog time-out ag (TO). These arithmetic/
logical operation and system management ags are used to record the status and operation of the
microcontroller.
With the exception of the TO and PDF ags, bits in the status register can be altered by instructions
like most other registers. Any data written into the status register will not change the TO or PDF ag.
In addition, operations related to the status register may give different results due to the different
instruction operations. The TO ag can be affected only by a system power-up, a WDT time-out or
by executing the "CLR WDT" or "HALT" instruction. The PDF ag is affected only by executing
the "HALT" or "CLR WDT" instruction or during a system power-up.
The Z, OV, AC, C, SC and CZ ags generally reect the status of the latest operations.
• C is set if an operation results in a carry during an addition operation or if a borrow does not take
place during a subtraction operation; otherwise C is cleared. C is also affected by a rotate through
carry instruction.
• AC is set if an operation results in a carry out of the low nibbles in addition, or no borrow from
the high nibble into the low nibble in subtraction; otherwise AC is cleared.
• Z is set if the result of an arithmetic or logical operation is zero; otherwise Z is cleared.
• OV is set if an operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit, or vice versa; otherwise OV is cleared.
• PDF is cleared by a system power-up or executing the "CLR WDT" instruction. PDF is set by
executing the "HALT" instruction.
• TO is cleared by a system power-up or executing the "CLR WDT" or "HALT" instruction. TO is
set by a WDT time-out.
• SC is the result of the "XOR" operation which is performed by the OV ag and the MSB of the
current instruction operation result.
• CZ is the operational result of different ags for different instuctions. Refer to register denitions
for more details.
In addition, on entering an interrupt sequence or executing a subroutine call, the status register will
not be pushed onto the stack automatically. If the contents of the status registers are important and if
the subroutine can corrupt the status register, precautions must be taken to correctly save it.