What value is loaded into CIO-CNTRL to configure the direction of Port B, and what does this configuration achieve?
Explanation
Initializing a Parallel I/O (PIO) chip involves writing specific control bytes to its internal registers to define the behavior of each port, such as the direction (input/output) of each pin. For Port B, the value $0F is used to create a mixed-direction port.
Other questions
In the analog signal averager design, what was the primary reason for putting the display refresh task inside the interrupt handler instead of the main loop?
According to the global register usage list in Program 11.3, what is the function of data register D7?
What is the memory address assigned to the `stop-flag` variable in the RAM location definitions of Program 11.3?
In the program's main loop, what is the purpose of the `BTST #START-BIT, CIO-PA-DATA` instruction followed by `BNE wait-for-zero`?
What is the reason given for using indirect addressing through a register (e.g., `MOVE.B (A3),D0`) instead of absolute addressing (e.g., `MOVE.B ADCO,DO`) for accessing ports?
In the `get-data-int` interrupt handler routine, after an ADC value is read and added to the accumulator, what is the next step if the dwell count is not yet zero (BNE z_pulse)?
What is the calculated execution time for the `idle` interrupt handler entry, including vectoring and return?
In the software debounce routine, after waiting for the START switch to be open, how many loops does the `check-debounce` routine execute to ensure the switch remains open before proceeding?
What is the purpose of the `bad-int` interrupt handler routine?
In the `update` subroutine, how is the correct value from the `norm-array` selected for autoscaling?
What is the initial value loaded into the `int5-vect` location during the `reset-entry` sequence?
Which condition leads to the longest execution time (114 microseconds) for the interrupt service routine?
Why is the `clear-arrays` subroutine considered a 'fastest looping primitive'?
In the `stop-sweep` routine, what is the purpose of the instruction `ST stop-flag`?
What does the `decode-tbl` lookup table in the assembly program contain?
When initializing the timer, two bytes are written to set the counting modulus of 400. What are these two bytes?
What is the function of address register A2 in the global register usage plan?
At the very beginning of the ROM code, what two 32-bit values are defined before the first executable statement?
In the `comp-and-save` subroutine, what is the purpose of the `BCHG #7, D1` instruction?
What is the memory address defined for the `data-array` in the program listing?
In the `wait-trig-int` routine, what happens if the external trigger signal (EXT-TRIGGER) is NOT present?
What is the primary pathology of using a software pulse for the Z-axis if interrupts are running?
How many times per second is the complete 256-point graph displayed when the refresh is handled by the interrupt routine?
In the `auto-scale` section of the `update` subroutine, why does the code perform `TST.W D2` before the `DIVS D2, D1` instruction?
What is the defined memory address for the LED port?
Which address register is reserved to point to the `NORM` array?
When checking for a manual abort at the end of a sweep, the code tests the STOP-BIT. If the bit is set, to which routine does the program branch?
What is the specified purpose of the `1's catching` input option for the STOP switch?
What does the instruction `MOVE.B #$E0, CIO-CNTRL` accomplish in the Port A initialization sequence?
What is the purpose of address register A3, according to the global register usage plan?
In the `idle-int` routine, what is the purpose of the instruction `ADDQ.B #1, D4`?
What is the starting address of the `norm-array` in RAM?
In the `sweep-start-int` routine, what is the primary action taken before falling through to `get-data-int`?
What is the execution time for the `getdata` interrupt handler entry at the end of a bin?
According to the `main-loop` logic, after the START switch is pressed and the control panel is read, what is the next major step before entering the `update-loop`?
In the `z_pulse` routine, what instructions are used to clear the timer's interrupt request?
What is the function of the `ASL.W #1, DO` instruction when reading the control panel?
Which port bit assignment corresponds to the `SWEEP-BIT` output?
What is the primary function of the `re-trigger` routine at the end of a sweep?
In Program 11.3, what is the value of `DACO_OFFSET`?
What does the instruction `EXT.L D3` accomplish in the `get-data-int` routine?
How is the `dwell_per_bin` parameter determined by the main program?
What instruction is used to turn off the SWEEP LED at the end of a sweep?
In the `vect-init-loop`, the `DBF` instruction loops until the D0 register equals what value?
What action does the `CLR.B stop-flag` instruction perform in the final setup before data collection?
What is the purpose of the `NOP` instruction in the `get-data-int` handler?
Which bit of Port A is assigned to the START button input?
What does the `BRA main-loop` instruction at the end of the `update-loop` signify?
In the Port C initialization, what value is loaded to set the port's direction, and what is the result?