1225

Manuals – Specifications – Links – Pictures

The Tektronix 1225 is a logic analyzer introduced in 1988 that supports 16 to 48 channels, 100 MHz asynchronous, 25 MHz synchronous.

The 1225 is equivalent to the Tektronix 1220 but has one more 16-bit probe input. It is also very similar to the Tektronix 1230 on the outside, but on the inside the layout is different − the 1225 has three probe inputs instead of four and the boards are stacked horizontally instead of vertically.

The 1225 was one of Tektronix' efforts to make an "easy to use" logic analyzer aimed at students and engineers. The user interface clearly represents that mindset. The menus are simple and there are help guides everywhere guiding the user in what he might want to do.

The 1225 did not have the same expansion capability that the 1230 had. The only expansion available were the option boards, of which four were available − parallel printer interface, RS-232 interface, GPIB interface, and on-line notes in foreign languages. Tektronix also had a software package (S43R101) that would run on IBM PC compatible machines.

A test card was supplied with the analyzer 671-0049-00.

See the Microprocessor support table for microprocessor disassembly configuration options.

Key Specifications

Probes	either P6442, P6443 or P6444 (16-channel)
Number of channels	48 channels
CRT	13 cm × 10 cm
Power	90-250 V
Weight	8.6 kg (19 lb.)
Features	Composite output RS-232 (optional) Printer port

Internals

The 1225 is built around a 65C02 as the control processor with 104K of SRAM, and 128K of firmware in a bank of EPROMs. There is a separate board under it that manages the display and keypad, which is powered by another 65C02 CPU. It is using an MC68A45 CRT controller to drive the display. The CRT is a Wells Gardner 7V3030. The display board has 56K of RAM and 8K of ROM. There are two coin cell batteries to retain settings. There is a bug that prevents the 1225 from keeping the date after the year 2000. Upon powering it off and on again it will revert to 19xx, e.g. 2018 will turn into 1918. The keypad switches have a tendency to become very "bouncy". See the page "repairs" tab for details.

Easter egg

An "Easter egg" can be activated in the 1225 by pressing the STOP button when the welcome screen shows during power-up. A bar with the programmers' names will display near the bottom of the screen.

Links

• MD's 1230 page
• Tek 1225 ROM dumps on MD's Tek 1230 page

Pictures

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Components

Some Parts Used in the 1225

Part	Part Number(s)	Class	Description	Used in
MOS Technology 6502	156-1425-00	Monolithic integrated circuit	8-bit microprocessor	1220 • 1225 • 1230 • DC5010