PIC12F635/PIC16F636/639
FIGURE 11-19:
CS
DETAILED SPI INTERFACE TIMING (AFE)
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
SCLK
SDIO
MSb
LSb
Data Byte
Row
Parity Bit
Command
Address
11.32.2.1 Clamp On Command
11.32.2.5 AGC Preserve On Command
This command results in activating (turning on) the
modulation transistors of all enabled channels; channels
enabled in Configuration Register 0 (Register 11-1).
This command results in preserving the AGC level
during each AGC settling time and apply the value to
the data slicing circuit for the following data stream. The
preserved AGC value is reset by a Soft Reset, and a
new AGC value is acquired and preserved when it
starts a new AGC settling time. This feature is disabled
by an AGC Preserve Off command (see Section 11.19
“AGC Preserve”).
11.32.2.2 Clamp Off Command
This command results in de-activating (turning off) the
modulation transistors of all channels.
11.32.2.3 Sleep Command
11.32.2.6 AGC Preserve Off Command
This command places the AFE in Sleep mode –
minimizing current draw by disabling all but the
essential circuitry. Any other command wakes the AFE
(example: Clamp Off command).
This command disables the AGC preserve feature and
returns the AFE to the normal AGC tracking mode, fast
tracking during AGC settling time and slow tracking
after that (see Section 11.19 “AGC Preserve”).
11.32.2.4 Soft Reset Command
11.32.3 CONFIGURATION REGISTERS
The AFE issues a Soft Reset when it receives an
external Soft Reset command. The external Soft Reset
command is typically used to end a SPI communication
sequence or to initialize the AFE for the next signal
detection sequence, etc. See Section 11.20 “Soft
Reset” for more details on Soft Reset.
The AFE includes 8 Configuration registers, including a
column parity register and AFE Status Register. All
registers are readable and writable via SPI, except
STATUS register, which is readable only. Bit 0 of each
register is a row parity bit (except for the AFE Status
Register 7) that makes the register contents an odd
number.
If a Soft Reset command is sent during a “Clamp-on”
condition, the AFE still keeps the “Clamp-on” condition
after the Soft Reset execution. The Soft Reset is
executed in Active mode only, not in Standby mode.
The SPI Soft Reset command is ignored if the AFE is
not in Active mode.
DS41232D-page 122
© 2007 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
