9/20/6Lecture 12 - Interfacing Devices1 Interfacing Devices to the 68000

9/20/6Lecture 12 - Interfacing Devices2 Interfacing devices  Read cycle timing parameters.  Write cycle timing parameters  Memory Device parameters  Other device issues

9/20/6Lecture 12 - Interfacing Devices3 Read cycle timing  For interfacing the arrows matter  Indicate the precedence of signals for interfacing

9/20/6Lecture 12 - Interfacing Devices4 Timing continued  For a slower device  How fast/slow a device can be interfaced?  t DALDI is 0 to 90ns  But this is FROM memory

9/20/6Lecture 12 - Interfacing Devices5 Parameters  Read cycle parameters

9/20/6Lecture 12 - Interfacing Devices6 Memory timing  Must consider timing of memory device

9/20/6Lecture 12 - Interfacing Devices7 Memory Pinout of the 6116 static RAM

9/20/6Lecture 12 - Interfacing Devices8 Items of note  Chip is 2K x 8-bit  Data word is a byte  Must use LDS* and UDS* when configuring memory with the device  In general memory chips are 1-bit, 1-byte, or 1-word in width of the data interface.

9/20/6Lecture 12 - Interfacing Devices9 Connecting up the 6116

 Ended here on Monday 11/15 9/20/6Lecture 12 - Interfacing Devices10

9/20/6Lecture 12 - Interfacing Devices11 Combined 68000, 6116 timing

9/20/6Lecture 12 - Interfacing Devices12 The write cycle  Timing of processor and memory device must work for both reading device and writing device  It is possible that timing will work for read but not for write for a given device  I/O devices may be such that they are only written to or read from  Example: On modern motherboards you may need matched DIMMs in pairs for the faster memory access speeds. (4GB Dual Channel DDR3 RAM – PC12800, 1600MHz (2x2048MB)

9/20/6Lecture 12 - Interfacing Devices13 Write cycle timing

9/20/6Lecture 12 - Interfacing Devices14 Write cycle parameters

9/20/6Lecture 12 - Interfacing Devices15 Write cycle timing of 6116

9/20/6Lecture 12 - Interfacing Devices combination for write

9/20/6Lecture 12 - Interfacing Devices17 General notes  Can use memory or I/O devices that are designed for the processor family Easy generation and use of interface pins such as CS*, AS*, DTACK*, etc. Little glue logic (sometimes almost none)  Use of generic memory and I/O devices May need a fair amount of glue logic and have to generate some signals May be slower than family devices

9/20/6Lecture 12 - Interfacing Devices18 General methodology  Read cycle timing parameters and specifically those that matter in device interfacing  Then the same for write  Memory chip timing parameters and how they matches (or don’t) with what we havd