Power & Display (F9H)
Supply rails, NCV beeper sync, PT1.2 state. Bits 7,6 are reserved — do not change.
UI Behavior (FAH)
mV range layout, backlight pin behavior, long-press functions, clamp vs. multimeter mode.
Timers
Hardware Modes (FDH)
Frequency range, UART format, PT1.2 LED usage, low-voltage power-off delay.
Counts & Switching
Overload & Warning Thresholds
Environment
Rotary-switch function assignment (80H–BFH)
DTM0660 reads four GPIO pins PT2.7..PT2.4 (MEA4..MEA1) as a 4-bit rotary-position code (0–15). For each position, four function slots are stored at addresses
0x80 + pos, 0x90 + pos, 0xA0 + pos, 0xB0 + pos. The user cycles through the four slots with the SELECT key. A position with all slots = 00H is unused (rotary detent skipped). Pin convention: floating = 1, tied to VSS = 0. PT2.4 is the LSB.Function code reference (section 11.3)
All 31 function codes the firmware recognises. Per-meter jumper wiring (J1A, J3, J4 …) determines which codes the analog front-end will actually handle correctly.
NCV Display Segment (1EH)
Which 7-segment LCD segment the NCV indicator drives. Bits 0–6 = a,b,c,d,e,f,g. Default: G only (0x40).
Electrocalc