| ??? 02/19/08 22:14 Read: times |
#151177 - Roll 'yer own, and get exactly what you want Responding to: ???'s previous message |
How about using a CPLD?
You can build the input from the MCU any way you like, and keep the bus load down to just one on P0 and P2. You could even make it serial if you have time. I don't know how many I/O's you need, or what characteristics they need, but there are many low-cost CPLD's that will suit purpose such as this for well under the cost of some dedicated devices. I don't know what the repertoire offers any longer, as I generally build my own I/O hardware in programmable logic. A CPLD with the equivalent of 36 '574's and the necessary decoding logic costs less than the '574's and logic would cost and is about the size of a quarter in tqfp packaging. The advantage, of course, is that you get EXACTLY what you need by way of logic functions and registers. RE |
| Topic | Author | Date |
| lots of i/o | 01/01/70 00:00 | |
| There are 16-bit Expanders | 01/01/70 00:00 | |
| The + and - of the slave processor | 01/01/70 00:00 | |
| the logical solution is to ... | 01/01/70 00:00 | |
| Roll 'yer own, and get exactly what you want | 01/01/70 00:00 | |
| why bother | 01/01/70 00:00 | |
| you're right, if "conventional" I/O ports are OK | 01/01/70 00:00 | |
| Max 7301 | 01/01/70 00:00 | |
| lots of i/o part 2 | 01/01/70 00:00 | |
| Theres a 40way NXP I/O expander | 01/01/70 00:00 | |
| Simple Distributed Concept | 01/01/70 00:00 | |
| very valid point | 01/01/70 00:00 | |
| For sure.....the multi-port job.... | 01/01/70 00:00 | |
| lots of i/o part 3 | 01/01/70 00:00 | |
| I love slave processors | 01/01/70 00:00 | |
MCP23008 | 01/01/70 00:00 |