PC87108 Datasheet | National Semiconductor

Description The PC87108 is a serial munications device with infrared capability It supports 6 modes or operation and is backward patible with the 16550 and 16450 The operational modes are UART Sharp-IR Ir DA 1 0 SIR Ir DA 1 1 MIR and FIR and Consumer Remote Control (monly referred to as TV Remote) Two methods are provided to access the internal registers an internal 16-bit address decoder or an externally generated chip select in bination with an internal 4-bit address decoder are used to generate the internal register select When the internal 16-bit address decoder is used any one of four PC M port legacy addresses can be selected as the base address In order to support existing legacy software using the 16550 UART the PC87108 provides a special fallback mechanism that automatically switches the device to 16550 patibility mode when the standard baud generator divisor registers are accessed The device architecture has been optimized to meet the requirements of a variety of UART and infrared based applications DMA support for all operational modes has been incorporated into the architecture Routing for interrupt and DMA handshake signals is provided to meet Plug-and-Play as well as PC’95 requirements The device can use either 1 or 2 DMA channels One channel is required for infrared based applications since infrared munications work in half duplex fashion Two channels would normally be needed to handle high-speed full duplex UART based applications To further ease driver design and simplify the implementation of infrared protocols a 12-bit timer with 1 ms resolution has also been included Features Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Fully patible with 16550 and 16450 devices Enhanced UART mode Sharp-IR with selectable internal or external modulation Ir DA 1 0 SIR with up to 115 2 kbps data rate Ir DA 1 1 MIR and FIR with 1 152 and 4 0 Mbps data rates Consumer remote control mode UART mode baud rates up to 1 5 Mbps Back-to-back infrared frame...