PC16552DV

PC16552D Dual Universal Asynchronous Receiver Transmitter with FIFOs June 1995 PC16552D Dual Universal Asynchronous Receiver Transmitter with FIFOs General Description The PC16552D is a dual version of the PC16550D Universal Asynchronous Receiver Transmitter (UART) The two serial channels are completely independent except for a common CPU interface and crystal input On power-up both channels are functionally identical to the 16450 Each channel can operate with on-chip transmitter and receiver FIFOs (FIFO mode) to relieve the CPU of excessive software overhead In FIFO mode each channel is capable of buffering 16 bytes (plus 3 bits of error data per byte in the RCVR FIFO) of data in both the transmitter and receiver All the FIFO control logic is on-chip to minimize system overhead and maximize system efficiency Signalling for DMA transfers is done through two pins per channel (TXRDY and RXRDY) The RXRDY function is multiplexed on one pin with the OUT 2 and BAUDOUT functions The CPU can select these functions through a new register (Alternate Function Register) Each channel performs serial-to-parallel conversion on data characters received from a peripheral device or a MODEM and parallel-to-serial conversion on data characters received from the CPU The CPU can read the complete status of each channel at any time Status information reported includes the type and condition of the transfer operations being performed by the DUART as well as any error conditions (parity overrun fra...