EM357-MOD-LR-ANT-TG Ember, EM357-MOD-LR-ANT-TG Datasheet - Page 101

• Manufacturer Part Number: EM357-MOD-LR-ANT-TG
• Description: MODULE EM357 PA/LNA W/ANT TG
• Manufacturer: Ember

Specifications of EM357-MOD-LR-ANT-TG

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Voltage - Supply: 2.1 V ~ 3.6 V
• Current - Receiving: 25mA
• Current - Transmitting: 42mA
• Data Interface: PCB, Surface Mount
• Memory Size: 192kB Flash, 12kB RAM
• Antenna Connector: On-Board, Chip
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Applications: -
• Sensitivity: -
• Other names: 636-1020

The UART is best operated in systems where the other side of the communication link also uses a crystal as its
timing reference, and baud rates should be selected to minimize the baud rate mismatch to the crystal
tolerance. Additionally, UART protocols should contain some form of error checking (for example CRC) at the
packet level to detect, and retry in the event of errors. Since the probability of corruption is low, there would
only be a small effect on UART throughput due to retries.
Errors may occur when:
where
For example, if the baud rate tolerance between receive and transmit is 200 ppm (reasonable if both sides are
derived from a crystal), and the baud rate is 115200 bps, then errors will not occur until the inter-byte gap
exceeds 43 ms. If the gap is exceeded then the chance of an error is essentially random, with a probability of
approximately P = baud / 24e6. At 115200 bps, the probability of corruption is 0.5%.
The UART character frame format is determined by four bits in the SC1_UARTCFG register:
A UART character frame contains, in sequence:
Figure 8-3 shows the UART character frame format, with optional bits indicated. Depending on the options
chosen for the character frame, the length of a character frame ranges from 9 to 12 bit times.
Note that asynchronous serial data may have arbitrarily long idle periods between characters. When idle,
serial data (TXD or RXD) is held in the high state. Serial data transitions to the low state in the start bit at the
beginning of a character frame.
Tgap
Tgap = inter-byte gap in seconds
baud = baud rate in bps
Ferror = relative frequency error in ppm
SC_UART8BIT specifies the number of data bits in received and transmitted characters. If this bit is clear,
characters have 7 data bits; if set, characters have 8 data bits.
SC_UART2STP selects the number of stop bits in transmitted characters. (Only one stop bit is required in
received characters.) If this bit is clear, characters are transmitted with one stop bit; if set, characters are
transmitted with two stop bits.
SC_UARTPAR controls whether or not received and transmitted characters include a parity bit. If
SC_UARTPAR is clear, characters do not contain a parity bit, otherwise, characters do contain a parity bit.
SC_UARTODD specifies whether transmitted and received parity bits contain odd or even parity. If this bit
is clear, the parity bit is even, and if set, the parity bit is odd. Even parity is the exclusive-or of all of the
data bits, and odd parity is the inverse of the even parity value. SC_UARTODD has no effect if SC_UARTPAR
is clear.
The start bit
The least significant data bit
The remaining data bits
If parity is enabled, the parity bit
The stop bit, or bits, if 2 stop bits are selected.
≥
(
baud
106
∗
Ferror
)
Final
8-26
EM351 / EM357
120-035X-000G