Architecture - Philips LPC2119 User Manual

Philips Semiconductors Preliminary User Manual
ARM-based Microcontroller LPC2119/2129/2292/2294

ARCHITECTURE

The architecture of the UART0 is shown below in the block diagram.
The VPB interface provides a communications link between the CPU or host and the UART0.
The UART0 receiver block, U0Rx, monitors the serial input line, RxD0, for valid input. The UART0 Rx Shift Register (U0RSR)
accepts valid characters via RxD0. After a valid character is assembled in the U0RSR, it is passed to the UART0 Rx Buffer
Register FIFO to await access by the CPU or host via the generic host interface.
The UART0 transmitter block, U0Tx, accepts data written by the CPU or host and buffers the data in the UART0 Tx Holding
Register FIFO (U0THR). The UART0 Tx Shift Register (U0TSR) reads the data stored in the U0THR and assembles the data to
transmit via the serial output pin, TxD0.
The UART0 Baud Rate Generator block, U0BRG, generates the timing enables used by the UART0 Tx block. The U0BRG clock
input source is the VPB clock (pclk). The main clock is divided down per the divisor specified in the U0DLL and U0DLM registers.
This divided down clock is a 16x oversample clock, NBAUDOUT.
The interrupt interface contains registers U0IER and U0IIR. The interrupt interface receives several one clock wide enables from
the U0Tx and U0Rx blocks.
Status information from the U0Tx and U0Rx is stored in the U0LSR. Control information for the U0Tx and U0Rx is stored in the
U0LCR.
UART0 119 January 08, 2004