⏱ Chip Timing Waveform Analyzer

Ben Eater 6502 Series — Video 6: RAM & Bus Timing — 62256 RAM vs 65C02 CPU Read Cycle
1.00 MHz
Period: 1000 ns  |  PHI2 half: 500 ns

Configuration

1.0 MHz
15 ns

Timing Margin Analysis

CheckBudgetNeedMargin

Timing OK

65C02 CPU Timing (fixed)

tADS = 30 ns max (PHI2↓ → Address valid)

tAH  = 10 ns min (Address hold after PHI2↑)

tMDS = 10 ns min (Data must be valid before PHI2↑)

tDHR = 10 ns min (Data hold after PHI2↑)

Read Cycle Timing Diagram — One Complete Clock Cycle

PHI2 Clock
Address Valid
CS* / OE* Active
Data Valid
Deadline (tMDS)
Timing Violation

62256 Read Cycle Parameters (Datasheet)

ParameterSymbol ‑5 Min‑5 Max ‑7 Min‑7 Max ‑8 Min‑8 Max Unit
Read cycle timetRC55—70—85—ns
Address access timetAA—55—70—85ns
Chip select to access timetACS—55—70—85ns
Output enable to output validtOE—35—40—45ns
Chip select to output in low-ZtCLZ5—10—10—ns
Output enable to output in low-ZtOLZ5—5—5—ns
Chip deselect to output in high-ZtCHZ020025030ns
Output disable to output in high-ZtOHZ020025030ns
Output hold from address changetOH5—5—5—ns