LPC1837FET256,551 NXP Semiconductors, LPC1837FET256,551 Datasheet - Page 739

• 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
<Document ID>
User manual
32.6.4 Smart card mode
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 an 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 the DIR pin as a direction control output signal.
Setting RS485CTRL bit 4 = ‘1’ enables this feature.
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 the
direction control pin.
RS485/EIA-485 driver delay time
The driver delay time is the delay between the last stop bit leaving the TXFIFO and the
de-assertion of the DIR pin. 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 DIR pin can be reversed by programming
bit 5 in the RS485CTRL 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.
Figure 92
shows a typical asynchronous smart card application.
All information provided in this document is subject to legal disclaimers.
Rev. 00.13 — 20 July 2011
Chapter 32: LPC18xx USART0_2_3
UM10430
© NXP B.V. 2011. All rights reserved.
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