LPC1837FET256,551 NXP Semiconductors, LPC1837FET256,551 Datasheet - Page 767

• Manufacturer Part Number: LPC1837FET256,551
• Description: Microcontrollers (MCU) 32BIT ARM CORTEX-M3 MCU 136KB SRAM
• Manufacturer: NXP Semiconductors
• Series: LPC18xxr

Specifications of LPC1837FET256,551

• Core: ARM Cortex M3
• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 150MHz
• Connectivity: CAN, EBI/EMI, Ethernet, I²C, Microwire, SD/MMC, SPI, SSI, SSP, UART/USART, USB OTG
• Peripherals: Brown-out Detect/Reset, DMA, I²S, Motor Control PWM, POR, PWM, WDT
• Number Of I /o: 80
• Program Memory Size: 1MB (1M x 8)
• Program Memory Type: FLASH
• Eeprom Size: -
• Ram Size: 136K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 3.6 V
• Data Converters: A/D 16x10b; D/A 1x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 256-LBGA
• Lead Free Status / Rohs Status: Details
• Other names: 935293795551

NXP Semiconductors
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User manual
Setting the RS485CTRL bit 0 enables this mode. In this mode, an address is detected
when a received byte causes the UART to set the parity error and generate an interrupt.
If the receiver is DISABLED (RS485CTRL bit 1 = ‘1’) any received data bytes will be
ignored and will not be stored in the RXFIFO. When an address byte is detected (parity bit
= ‘1’) it will be placed into the RXFIFO and an Rx Data Ready Interrupt will be generated.
The processor can then read the address byte and decide whether or not to enable the
receiver to accept the following data.
While the receiver is ENABLED (RS485CTRL bit 1 =’0’) all received bytes will be
accepted and stored in the RXFIFO regardless of whether they are data or address. When
an address character is received a parity error interrupt will be generated and the
processor can decide whether or not to disable the receiver.
RS-485/EIA-485 Auto Address Detection (AAD) mode
When both RS485CTRL register bits 0 (9-bit mode enable) and 2 (AAD mode enable) are
set, the UART is in auto address detect mode.
In this mode, the receiver will compare any address byte received (parity = ‘1’) to the 8-bit
value programmed into the RS485ADRMATCH register.
If the receiver is DISABLED (RS485CTRL bit 1 = ‘1’) any received byte will be discarded if
it is either a data byte OR an address byte which fails to match the RS485ADRMATCH
value.
When a matching address character is detected it will be pushed onto the RXFIFO along
with the parity bit, and the receiver will be automatically enabled (RS485CTRL bit 1 will be
cleared by hardware). The receiver will also generate n Rx Data Ready Interrupt.
While the receiver is ENABLED (RS485CTRL bit 1 = ‘0’) all bytes received will be
accepted and stored in the RXFIFO until an address byte which does not match the
RS485ADRMATCH value is received. When this occurs, the receiver will be automatically
disabled in hardware (RS485CTRL bit 1 will be set), The received non-matching address
character will not be stored in the RXFIFO.
RS-485/EIA-485 Auto Direction Control
RS485/EIA-485 Mode includes the option of allowing the transmitter to automatically
control the state of either the RTS pin or the DTR pin as a direction control output signal.
Setting RS485CTRL bit 4 = ‘1’ enables this feature.
Direction control, if enabled, will use the RTS pin when RS485CTRL bit 3 = ‘0’. It will use
the DTR pin when RS485CTRL bit 3 = ‘1’.
When Auto Direction Control is enabled, the selected pin will be asserted (driven low)
when the CPU writes data into the TXFIFO. The pin will be de-asserted (driven high) once
the last bit of data has been transmitted. See bits 4 and 5 in the RS485CTRL register.
The RS485CTRL bit 4 takes precedence over all other mechanisms controlling RTS (or
DTR) with the exception of loopback mode.
RS485/EIA-485 driver delay time
All information provided in this document is subject to legal disclaimers.
Rev. 00.13 — 20 July 2011
Chapter 33: LPC18xx UART1
UM10430
© NXP B.V. 2011. All rights reserved.
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