User manual

Signal Analysis PICtail™ Daughter Board User’s Guide
DS51476A-page 10  2004 Microchip Technology Inc.
FIGURE 1-3: SIGNAL ANALYSIS ELECTRICAL CONNECTION BLOCK
DIAGRAM
1.5 PIC16F684 FIRMWARE
This section provides a high-level discussion of the PIC16F684 firmware ‘PICA2Dlab’.
The source code for PICA2Dlab is contained on the PICkit 1 Flash Starter Kit CD-ROM.
When programmed into the PIC16F684 on the Signal Analysis PICtail Daughter Board,
PICA2Dlab recognizes commands from the PICkit 1 Flash Starter Kit PIC16C745
PICmicro device with USB. The PIC16C745 requires firmware version 2.0.0 or later for
the signal analysis functions to work. PICA2Dlab communicates synchronously in both
directions with the PIC16C745 microcontroller. Finally, the PICkit 1 Signal Analysis PC
host program can command the PIC16F684 on the Signal Analysis PICtail Daughter
Board.
1.5.1 PICA2Dlab Commands
Once programmed into the PIC16F684 microcontroller, the PICA2Dlab.hex firmware
receives commands from the PC16C745. Presently it understands five commands:
1. Version – Returns a single byte representing a version number for the code. The
host program on the PC may interrogate this to ensure the proper code is
installed in the PIC16F684.
2. Get Real-time Data – Runs a conversion and returns the two byte result.
3. Set Configuration – Expects two bytes from the host. First byte represents the
number of 256 byte blocks to acquire. Second byte represents the acquisition
speed which is used as an index into a look-up table and sets up Timer0 for the
acquisition period.
4. Go – Starts the acquisition process.
5. Read – Reads the data stored in the serial EEPROMs and sends it to the PC via
the USB port.
PICkit™ 1 Flash Starter Kit
Signal Analysis PICtail™
Daughter Board
Personal
Computer
USB
RB7
PIC16C745
RC7
RC6
RA0
RA1
RC2
28
18
17
2
3
13
7
13
+5V+5V
8
VPP
Charge Pump
Circuitry
3
13
7
8
3
14 14
+5V
ICSPDAT
ICSPCLK
V
PP
GND
+5V
13
12
4
RA0
RA1
RA3
PIC16F684
Busy
P1
J3