CHAPTER 12 BIT SEQUENTIAL BUFFERUser’s Manual U14826EJ5V0UD13412.4 Bit Sequential Buffer OperationSet as follows to operate the bit sequential buffer.<1> Set values to bit sequential buffer 10 data registers L and H (BSFRL10, BSFRH10)<2> Set the bit sequential buffer to operation enabled (BSFE10 = 1)If the LSB of BSFRL10 is being output at P20/BSFO/TMO, set P20 to output mode (PM20 = 0) and theoutput latch of P20 to 0<3> Start the clock operationIf the clock is input before the bit sequential buffer starts operation, the output time of the start bit may be shorterthan one cycle of the clock when output commences, as shown in the figure below.2AAAH 0AAAH5555H 1555Ht0t1 t2t1< t0 t2 = t0BSFE10Timer 40match signalBSFRL10,BSFRH10Bit sequentialbuffer outputFigure 12-4 shows the operation timing of the bit sequential buffer.Figure 12-4. Operation Timing of Bit Sequential Buffer2AAAH 0AAAH1555HBSFE10Timer 40match signalBSFRL10,BSFRH10Bit sequentialbuffer outputUndefined 5555H ×555H ×2AAHCautions 1. Even if data is written to the data register while the bit sequential buffer is operating, theshift clock (timer 40 match signal) will not stop. Data should therefore be written to thedata register when the shift clock is low level.2. The value of the data register is undefined after a shift.Remark ×: Undefined
