Synchronizing control of test instruments

A method for synchronizing a plurality of test devices coupled to a host, comprising:

• initializing a counter of each of the plurality of test devices substantially simultaneously;
• incrementing each of the counters substantially simultaneously when an increment message is received by respective ones of the plurality of test devices;
• triggering an action by at least one of the plurality of test devices when a respective counter of the at least one of the plurality of test devices reaches a programmed counter value;
• and
• triggering a second action by the at least one of the plurality of test devices when the respective counter of the at least one of the plurality of test devices reaches a second programmed counter value;
• wherein the first action is an application of at least one of a test current and a test voltage to a plurality of test components coupled to respective ones of the plurality of test devices;
• and wherein the second action is measurement of a resultant variable associated with the plurality of test components.

An apparatus for synchronizing a plurality of test devices coupled to a host, comprising:

• a first counter in a first of the plurality of test devices;
• a second counter in a second of the plurality of test devices;
• wherein the host is operable to transmit an initialization signal to the first counter and the second counter, the initialization signal initializing the first counter and the second counter to a starting counter value, and is operable to transmit a plurality of data frames, each of the plurality of data frames including a periodic signal indicating a start of a data stream and a respective data packet following the periodic signal and each of the plurality of data frames having a same time period;
• and wherein the first counter and the second counter are operable to increment to a new counter value each time the periodic signal of a respective data frame is received by the first and the second of the plurality of test devices;
• and
• one of a source signal and a measurement signal triggerable by the first and the second of the plurality of test devices when the first counter and the second counter reaches a programmed counter value;
• wherein
• the first of the plurality of test devices is operable to trigger a respective source signal when the first counter reaches a first programmed counter value;
• and the second of the plurality of test devices is operable to trigger a respective source signal when the second counter reaches the first programmed counter value;
• wherein
• the host is further operable to transmit an offset value to the first of the plurality of test devices and to the second of the plurality of test devices;
• and the apparatus further comprising:
• a first timer in the first of the plurality of test devices;
• and
• a second timer in the second of the plurality of test devices;
• and wherein the first of the plurality of test devices is operable to start the first timer when the first counter reaches a second programmed counter value and to trigger a respective measurement signal when the first timer reaches the offset value;
• and wherein the second of the plurality of test devices is operable to start the second timer when the second counter reaches the second programmed counter value and to send a respective measurement signal when the second timer reaches the offset value.

In an apparatus for testing a plurality of electronic components by applying a source signal to each of the electronic components and by measuring value of each of the electronic components after application of the source signal, the apparatus controlled by a host, the improvement comprising:

• a first source-measurement unit applying the source signal to selected ones of the plurality of electronic components and measuring the value of the selected ones of the plurality of electronic components;
• a second source-measurement unit applying the source signal to others of the plurality of electronic components and measuring the value of the others of the plurality of electronic components;
• a first counter in the first source-measurement unit;
• and
• a second counter in the second source-measurement unit;
• wherein the host is configured to send an initialization signal to initialize the first and second counters substantially simultaneously with respect to each other and is configured to transmit a plurality of data frames to each of the first source-measurement unit and the second source-measurement unit, each data frame having a same time period and including a periodic signal indicating a start of a data stream and a respective data packet following the periodic signal;
• wherein each of the first and second counters is configured to increment each time the periodic signal is received by the first and second source-measurement units while the plurality of data frames is transmitted from the host;
• and
• wherein the first source-measurement unit either applies the source signal or measures the value when the first counter reaches a programmed counter value and the second source-measurement unit performs a same action as the first source-measurement unit when the second counter reaches the programmed counter value.