Chip-Select Unit ......................................................................................................................... 49
Chip-Select Timing ......................................................................................................... 49
Ready and Wait-State Programming ............................................................................. 49
Memory Maps ................................................................................................................ 50
Chip-Select Overlap ....................................................................................................... 51
Upper Memory Chip Select ............................................................................................ 51
Low Memory Chip Select ............................................................................................... 51
Midrange Memory Chip Selects ..................................................................................... 51
Peripheral Chip Selects ................................................................................................. 52
Internal Memory ......................................................................................................................... 52
Interaction with External RAM ........................................................................................ 52
Emulator and Debug Modes .......................................................................................... 52
Refresh Control Unit .................................................................................................................. 53
Interrupt Control Unit ................................................................................................................. 53
Programming the Interrupt Control Unit ......................................................................... 53
Timer Control Unit ...................................................................................................................... 53
Watchdog Timer ........................................................................................................................ 54
Direct Memory Access ............................................................................................................... 54
DMA Operation .............................................................................................................. 55
Asynchronous Serial Port/DMA Transfers ..................................................................... 55
DMA Channel Control Registers .................................................................................... 55
DMA Priority ................................................................................................................... 55
Asynchronous Serial Port .......................................................................................................... 56
DMA Transfers through the Serial Port .......................................................................... 56
Synchronous Serial Interface ..................................................................................................... 56
Four-Pin Interface .......................................................................................................... 57
Programmable I/O (PIO) Pins .................................................................................................... 57
Low-Voltage Operation .............................................................................................................. 59
Low-Voltage Standard ................................................................................................... 59
Power Savings ............................................................................................................... 59
Input/Output Circuitry ..................................................................................................... 59
Absolute Maximum Ratings ....................................................................................................... 60
Operating Ranges ...................................................................................................................... 60
DC Characteristics Over Commercial and Industrial Operating Ranges ................................... 60
Thermal Characteristics ............................................................................................................. 61
TQFP Package .............................................................................................................. 61
Typical Ambient Temperatures ...................................................................................... 62
Commercial and Industrial Switching Characteristics and Waveforms ...................................... 67
Key to Switching Waveforms ......................................................................................... 67
Alphabetical Key to Switching Parameter Symbols ....................................................... 68
Numerical Key to Switching Parameter Symbols .......................................................... 69
Switching Characteristics over Commercial and Industrial Operating Ranges,
Read Cycle (25 MHz and 33 MHz) ................................................................................ 70
Switching Characteristics over Commercial and Industrial Operating Ranges,
Read Cycle (40 MHz and 50 MHz) ................................................................................ 71
Read Cycle Waveforms ................................................................................................. 72
Switching Characteristics over Commercial and Industrial Operating Ranges,
Write Cycle (25 MHz and 33 MHz) ................................................................................ 73
Switching Characteristics over Commercial and Industrial Operating Ranges,
Write Cycle (40 MHz and 50 MHz) ................................................................................ 74
Write Cycle Waveforms ................................................................................................. 75
Switching Characteristics over Commercial and Industrial Operating Ranges,
Internal RAM Show Read Cycle (25 MHz and 33 MHz) ................................................ 76
Am186TMER and Am188TMER Microcontrollers Data Sheet
7
AMD [ AMD ]
