Functional safety high-speed counter module including diagnostics circuitry for performing counter pattern test

A Functional Safety Counter Module, comprising:

• input circuitry configured to receive counter input signals from an encoder and output first and second counting signals;
• a first microcontroller including a first hardware counter, a second hardware counter, a first storage device that stores a first firmware algorithm code to execute a counter pattern test in order to detect a short or open input signal and/or a failure in counting capability of the first microcontroller;
• a second microcontroller including a third hardware counter, a fourth hardware counter, a second storage device that stores a second firmware algorithm code to execute the counter pattern test in order to detect a short or open input signal and/or a failure in counting capability of the second microcontroller;
• and
• test circuitry configured to receive a first test signal from the first microcontroller and to receive a second test signal from the second microcontroller,
• wherein the test circuitry is configured to drive the first and second counting signals being input to the first hardware counter, the second hardware counter, the third hardware counter and the fourth hardware counter,
• wherein the first firmware algorithm code enables a first counter out of the first hardware counter or the second hardware counter to be individually removed from normal operation, tested, and resynchronized without stopping counting applications,
• wherein the second firmware algorithm code enables a second counter out of the third hardware counter or the fourth hardware counter to be individually removed from normal operation, tested, and resynchronized without stopping counting applications, and
• wherein the first firmware algorithm code and the second firmware algorithm code
• are configured to resynchronize and restore respectively the first counter or the second counter after the counter pattern test and
• are configured to detect an offset and adjust during a resynchronization process to account for the offset, wherein separate resynchronization algorithm codes are used depending on an input frequency of counter signals input to the first hardware counter or the second hardware counter or the third hardware counter or the fourth hardware counter,
• wherein after completion of the counter pattern test a counter under test is resynchronized to an active counter by assigning a count of the counter under test to a count of the active counter that is running and being a counter that has not been tested, and
• wherein the separate resynchronization algorithm codes include a high-speed algorithm code being used for sinusoidal input frequencies at or above 125 kHz which sets the count of the counter under test to the count of the active counter and verifies the counter under test and the active counter match.

A method of testing a Functional Safety Counter Module, the method comprising:

• providing input circuitry configured to receive counter input signals from an encoder and output first and second counting signals;
• providing a first microcontroller including a first hardware counter, a second hardware counter, a first storage device that stores a first firmware algorithm code to execute a counter pattern test in order to detect a short or open input signal and/or a failure in counting capability of the first microcontroller;
• providing a second microcontroller including a third hardware counter, a fourth hardware counter, a second storage device that stores a second firmware algorithm code to execute the counter pattern test in order to detect a short or open input signal and/or a failure in counting capability of the second microcontroller;
• and
• providing test circuitry configured to receive a first test signal from the first microcontroller and to receive a second test signal from the second microcontroller,
• wherein the test circuitry is configured to drive the first and second counting signals being input to the first hardware counter, the second hardware counter, the third hardware counter and the fourth hardware counter,
• wherein the first firmware algorithm code enables a first counter out of the first hardware counter or the second hardware counter to be individually removed from normal operation, tested, and resynchronized without stopping counting applications,
• wherein the second firmware algorithm code enables a second counter out of the third hardware counter or the fourth hardware counter to be individually removed from normal operation, tested, and resynchronized without stopping counting applications, and
• wherein the first firmware algorithm code and the second firmware algorithm code
• are configured to resynchronize and restore respectively the first counter or the second counter after the counter pattern test and
• are configured to detect an offset and adjust during a resynchronization process to account for the offset, wherein separate resynchronization algorithm codes are used depending on an input frequency of counter signals input to the first hardware counter or the second hardware counter or the third hardware counter or the fourth hardware counter,
• wherein after completion of the counter pattern test a counter under test is resynchronized to an active counter by assigning a count of the counter under test to a count of the active counter that is running and being a counter that has not been tested, and
• wherein the separate resynchronization algorithm codes include a low-speed algorithm code being used for sinusoidal input frequencies below 125 kHz which calculates and applies the offset to the count of the counter under test to compensate for a scenario where a current position is at an edge in between encoder states.