21 REMOTE CONTROLLER (REMC)272 EPSON S1C17001 TECHNICAL MANUAL21.4 Data Length Counter Clock SettingsThe data length counter is an 8-bit counter for setting data lengths when transmitting data.When a value corresponding to the data pulse width is written during data transmission, the data length counter be-gins counting down from that value, generating an underflow interrupt factor and halting when the counter reaches 0.The subsequent transmit data is set using this interrupt.This counter is also used for data receiving, enabling measurement of the receive data length. Interrupts can be gen-erated at the input signal rising or falling edges when receiving data. The data pulse length can be obtained from thedifference between data pulses by setting the data length counter to 0xff using the interrupt when the input changesand by reading out the count value when a subsequent interrupt occurs due to input changes.This data length counter count clock also uses a prescaler output clock and can select one of 15 different types. Theprescaler output clock is selected by the control bit LCCLK[3:0] (D[3:0]/REMC_PSC register) provided separatelyto the carrier generation clock.∗ LCCLK[3:0]: Length Counter Clock Select Bits in the REMC Prescaler Clock Select (REMC_PSC) Register(D[3:0]/0x5341)Table 21.4.1: Data length counter clock selectionLCCLK[3:0] Prescaler output clock LCCLK[3:0] Prescaler output clock0xf Reserved 0x7 PCLK-1/1280xe PCLK-1/16384 0x6 PCLK-1/640xd PCLK-1/8192 0x5 PCLK-1/320xc PCLK-1/4096 0x4 PCLK-1/160xb PCLK-1/2048 0x3 PCLK-1/80xa PCLK-1/1024 0x2 PCLK-1/40x9 PCLK-1/512 0x1 PCLK-1/20x8 PCLK-1/256 0x0 PCLK-1/1(Default: 0x0)The data length counter can count up to 256. The count clock should be selected to ensure that the data length fitswithin this range.
