OM13005,598 NXP Semiconductors, OM13005,598 Datasheet - Page 95

• Manufacturer Part Number: OM13005,598
• Description: BOARD EVAL EM773 METER US PLUG
• Manufacturer: NXP Semiconductors
• Type: Other Power Managementr

Specifications of OM13005,598

• Design Resources: Plug Meter Schematics, Gerber Files USB Dongle Schematics, Gerber Files
• Main Purpose: Power Management, Energy/Power Meter
• Embedded: Yes, MCU, 32-Bit
• Utilized Ic / Part: EM773FHN33,551
• Interface Type: USB
• Maximum Operating Temperature: + 150 C
• Operating Supply Voltage: 1.8 V to 3.6 V
• Product: Power Management Development Tools
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Primary Attributes: -
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: EM773, OL2381
• Other names: 568-6680

NXP Semiconductors
9.7 Architecture
UM10415
User manual
The driver delay time is the delay between the last stop bit leaving the TXFIFO and the
de-assertion of RTS. This delay time can be programmed in the 8-bit RS485DLY register.
The delay time is in periods of the baud clock. Any delay time from 0 to 255 bit times may
be used.
RS485/EIA-485 output inversion
The polarity of the direction control signal on the RTS (or DTR) pins can be reversed by
programming bit 5 in the U0RS485CTRL register. When this bit is set, the direction control
pin will be driven to logic 1 when the transmitter has data waiting to be sent. The direction
control pin will be driven to logic 0 after the last bit of data has been transmitted.
The architecture of the UART is shown below in the block diagram.
The APB interface provides a communications link between the CPU or host and the
UART.
The UART receiver block, U0RX, monitors the serial input line, RXD, for valid input. The
UART RX Shift Register (U0RSR) accepts valid characters via RXD. After a valid
character is assembled in the U0RSR, it is passed to the UART RX Buffer Register FIFO
to await access by the CPU or host via the generic host interface.
The UART transmitter block, U0TX, accepts data written by the CPU or host and buffers
the data in the UART TX Holding Register FIFO (U0THR). The UART TX Shift Register
(U0TSR) reads the data stored in the U0THR and assembles the data to transmit via the
serial output pin, TXD1.
The UART Baud Rate Generator block, U0BRG, generates the timing enables used by the
UART TX block. The U0BRG clock input source is UART_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.
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 10 September 2010
Chapter 9: EM773 Universal Asynchronous Transmitter (UART)
UM10415
© NXP B.V. 2010. All rights reserved.
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