Manual

If Fosc= 14.85MHz:

RR2(5) = 2970 (dec), B9A (hex)

RR2(6.25) = 2376 (dec), 948 (hex)

RR2(10) = 1485 (dec), 5CD (hex)

RR2(12.5) = 1188 (dec), 4A4 (hex)

RR2(20) = NOT possible (result is not integer no.)

RR2(25) = 594 (dec), 252 (hex)

From above it is clear that we have 11 possible values for the combination of

2 Fosc and 6 Fc’s. When the Rvalue is read from the unit the current Fc and

Fosc. can be determined from these values.

Note: Rvalue is stored as 2 bytes in EEPROM locations 61, 62

3.4 IF

IF is the Intermediate Frequency of the receiver. Its value for the STn00

family is always zero, but for the SRn00 family is as follows:

SRn00 with frequency range < 200 MHz:, “High Side” (+45 MHz)

SRn00 with frequency range > 200 MHz, “Low Side” (- 45 MHz).

STn00, any frequency IF = 0

Note: The IF value is not stored in the unit’s EEPROM. The type of ST or

SRn00 must be known before programming can be carried out.

4 Channel Information and Storage

For both the ST and SRn00 family, 16 random and 112 sequential channels

can be stored in the non-volatile EEPROM memory area of the internal PIC

processor. Channels 0 - 15 are stored individually in the EEPROM and

channels 16 - 127 are calculated from the start frequency and the table step

increment.

In principle frequency is stored in a two byte format plus the high byte offset.

The data stored is not the frequency itself, but the frequency divided by the

Fc. In other words if the desired frequency for the random channel N is

Freq(N), then the value stored is F(N) where F(N) is calculated as:

F(N) = [Freq(N) + IF] / Fc

The result is stored as:

EEPROM(60) = int [F(N)/65536] *256 high byte offset

EEPROM(N) = int [F(N)/256] - EEPROM(60) msb

EEPROM(N + 16) = F(N)- [EEPROM(60) + EEPROM(N)] *256 lsb