cy8c3446lti-075es2 Cypress Semiconductor Corporation., cy8c3446lti-075es2 Datasheet - Page 22

• Manufacturer Part Number: cy8c3446lti-075es2
• Description: Psoc? 3 Cy8c34 Family Errata Silicon Revision Es2
• Manufacturer: Cypress Semiconductor Corporation.

33. VDAC Output
34. VDAC/IDAC Strobe
January 7, 2011
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PROBLEM DEFINITION
VDAC output produces a glitch of up to 100 ns on every DAC output update.
PARAMETERS AFFECTED
NA
TRIGGER CONDITIONS(S)
DAC output update.
SCOPE OF IMPACT
VDAC output produces a glitch on every DAC update. Update occurs on a CPU write or DSI strobe signal.
The glitch is noticed more prominently when it is buffered (due to the low output impedance of the buffer).
WORKAROUND
Glitches cannot be completely eliminated with a workaround. Glitches can be reduced by not buffering the
VDAC output or by adding capacitance to the output to filter the glitches. The glitch filter should be comprised
of a low pass filter with a cut off frequency below 1 MHz.
FIX STATUS
Silicon revision fix confirmed in production silicon.
PROBLEM DEFINITION
On each write to the VDAC/IDAC the DAC outputs the previously written data causing a one write delay to the
DAC output.
PARAMETERS AFFECTED
NA
TRIGGER CONDITION(S)
Writing new output data to the VDAC/IDAC.
SCOPE OF IMPACT
The VDAC/IDAC always outputs the previously written data for firmware updates. For hardware updates, the
hardware strobe always outputs the previously strobed data. The interface appears as if it has a two stage
pipeline between data writes/strobes and the DAC output.
WORKAROUND
Write (firmware) or strobe (hardware) the VDAC/IDAC twice with each update insuring the current data is
output form the DAC. DMA also requires two writes to update the DAC which can be achieved by chaining
two identical DMA Transaction Descriptors (TDs). The firmware workaround is already implemented in both
VDAC and IDAC Component Write APIs in PSoC Creator.
FIX STATUS
Silicon revision fix confirmed in production silicon.
Document Number: 001-61136 Rev. *C
Errata Document
PSoC
®
3: CY8C34 Family
22
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