User manual

MCP2030 Bidirectional Communication Demo Kit User’s Guide
© 2006 Microchip Technology Inc. DS51637A-page 13
The LF command Base Station Demo Board consists of a 125 kHz carrier modulated
as follows:
1: 4 ms ON for AFE’s AGC stabilization.
2: 500 µs OFF.
3: 2 ms ON followed by a 2 ms OFF (AFE’s output enable filter). This pattern is
dependant on the configuration setting of the receiving AFE.
4: 10 bit of command type (3C), parity, and Stop bit. The bits are transmitted Least
Significant bits (LSb) first. The data is encoded with PWM method. (see
Figure 3-2).
5: 50 ms ON for RSSI sample.
6: Waiting for a valid response from the Transponder.
FIGURE 3-2: PWM Data Encoding Format.
LOGIC ‘0’
LOGIC ‘1’
Bit Period
500 µs
250 µs
500 µs
250 µs