Atmel Wireless LAN Access Point Uživatelský manuál stáhnout pdf (Strana 12)

Atmel ATWILC1500-MR [PRELIMINARY DATASHEET]

Atmel-42376A-ATWINC1500-MR210P-SmartConnect-Datasheet_102014

5.3 UART Interface

Atmel ATWINC1500-MR210P has a Universal Asynchronous Receiver / Transmitter (UART) interface available

on pins J14 and J19. It can be used for control or data transfer if the baud rate is sufficient for a given

application. The UART is compatible with the RS-232 standard, where ATWINC1500-MR210PA operates as

Data Terminal Equipment (DTE). It has a two-pin RXD/TXD interface.

The UART features programmable baud rate generation with fractional clock division, which allows transmission

and reception at a wide variety of standard and non-standard baud rates. The UART input clock is selectable

between 10MHz, 5MHz, 2.5MHz, and 1.25MHz. The clock divider value is programmable as 13 integer bits and

3 fractional bits (with 8.0 being the smallest recommended value for normal operation). This results in the

maximum supported baud rate of 10MHz / 8.0 = 1.25MBd.

The UART can be configured for seven or eight bit operation, with or without parity, with four different parity

types (odd, even, mark, or space), and with one or two stop bits. It also has Rx and Tx FIFOs, which ensure

reliable high speed reception and low software overhead transmission. FIFO size is 4 x 8 for both Rx and Tx

direction. The UART also has status registers showing the number of received characters available in the FIFO

and various error conditions, as well the ability to generate interrupts based on these status bits.

An example of UART receiving or transmitting a single packet is shown in Figure 5-3 on page 12. This example

shows 7-bit data (0x45), odd parity, and two stop bits.

See the ATWINC1500-MR210PA Programming Guide for information on configuring the UART.

Figure 5-3. Example of UART Rx or Tx packet

Input hold time t

IHD

5 ns

Output delay t

ODLY

0 20 ns

Slave select setup time t

SUSSN

5 ns

Slave select hold time t

HDSSN

5 ns

Table 5-3. SPI Slave Timing Parameters (Continued)

Parameter Symbol Min Max Units

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 23 24

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Atmel Wireless LAN Access Point Uživatelský manuál Strana 12