User manual

Signal Analysis PICtail™ Daughter Board User’s Guide
DS51476A-page 8  2004 Microchip Technology Inc.
1.4.1 PCB Layout and Parts
Figure 1-1 shows the PCB layout of the Signal Analysis board. It is populated with a
PIC16F684 and two 25LC640 serial EEPROM memory devices. The PIC16F684 I/O
pins RC0, RC1 and RC3 are connected directly to test point connections on the edge
of the PCB. These can be configured as comparator analog inputs (RC0/AN4,
RC1/AN5), analog-to-digital converter inputs (RC0/AN4, RC1/AN5, RC3/AN7) or as
digital input/output pins. I/O pin RC5 is connected through a RC filter (R1 and C4) to a
test point connection. RC5 is the P1A output of the Enhanced Capture/Compare/Pulse
Width Modulation (ECCP) module. It can be configured for digital PWM output.
Additionally, +5V and ground test points are available as test point connections.
Two 25LC640 SPI™ compatible serial EEPROM memory devices provide 8-bit by 16K
bytes of non-volatile memory. They are used in conjunction with the signal analysis
firmware (PICA2Dlab.hex) program to store data at a specified sample rate. For non
real-time acquisition modes (oscilloscope, FFT and histogram), the PC program
downloads the data from the 25LC640’s for computation and display.
Connector J1 allows additional circuit boards (for example temperature, light or
pressure sensors) to be plugged into the Signal Analysis board for signal measurement
and analysis. All port pins from the PIC16F684 are available on the J1 connector.
FIGURE 1-1: SIGNAL ANALYSIS PICtail™ DAUGHTER BOARD
GND +5V
PICtail™ Daughter Board
Signal Analysis
RC5 RC0 RC1 RC3
C1
U1
U3
C3
C2
U2
R1
C4
J1
P1
RA5 RA4 RA3 RC5 RC4 RC3 RC0 RA1 RA2 RC0 RC1 RC2 +5V
GND