For our design, we used the Actel 1020B PLCC fpga which has 68 pins.
We managed to fit our design into the fpga with no major probelms.
Below are the results of the actmap estimate for the chip (which are not the
real results from designer).
| Final Estimated Results | |
|---|---|
| Comb. Modules: | 395 modules |
| Area: | 641 modules |
| Longest Path: | 112.8 ns |
| Max Levels: | 11 |
| IO Pins: | 49 |
| Clk Networks: | 1 |
| name | pin # | function |
|---|---|---|
| OUT_MCLK | 51 | output buffer from crystal format on chip oscillator |
| OUT_MCLK_SQ | 53 | Same as pin 51, except meant for external loads |
| R2_OUT | 46 | Output pin for RC oscillator (humidity capacitor oscillator) connected directly to R2 |
| CAP_OUT | 47 | Output pin for RC oscillator - directly to humidity capacitor |
| R1_IN | 48 | Input pin for RC oscillator - connected directly from R1 |
| IN_MCLK | 50 | Input for on chip ocillator using external crystal |
| FREQ_IN | 45 | Input for humidity dependent frequency - connect directly to pin 46 |
| CLOCK | 52 | Input for master system clock - connect directly to pin 53 |
| RESET | 68 | Global reset for internal state machines, registers and counters |
| HUMID | 62 | Output signal - high if desired humidity is higher than current humidity |
| KEYPAD_COLUMN0,1,2 | 33,30,31 | Input pins to determine which key was pressed |
| KEYPAD_ROW0,1,2,3 | 27,26,24,29 | Output pins to rotate active lows through rows of keypad |
| KEYPAD_MSD0,1,2,3 | 34,28,35,19 | Output pins for most significant digit of keypad input (desired humidity). Output is in BCD, with 3 being most significant bit. |
| KEYPAD_LSD0,1,2,3 | 22,20,18,23 | Output pins for the least significant digit of the keypad input (desired humidity). Output is in BCD, with 3 being the most significant bit. |
| VALUE_MSD0,1,2,3 | 6,9,17,12 | Output pins for the most significant digit of the current relative humidity. Output is in BCD, with 3 being the most significant bit. |
| VALUE_LSD0,1,2,3 | 11,10,8,7 | Output pins for the least significant digit of the current relative humidity. Output is in BCD, with 3 being the most significant bit. |
| FVAL10 - FVAL18 | 63,42,44,43,40,41,39,36,37,13 | Output debeg pins. Number of humidity frequency counter in a sample. FVAL18 is the most significant bit. |
| F_VALUE0 - F_VALUE6 | 13,64,16,65,1,60,61 | Output debug pins. The sampled humidity in binary. F_VALUE6 is the most significant bit. |
Note: The mode pin must be connected to GND for normal functionality.