cy8c3446lti-075es2 Cypress Semiconductor Corporation., cy8c3446lti-075es2 Datasheet - Page 9

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

January 7, 2011
6. Delta Sigma ADC Output Count
7. Delta Sigma ADC End-of-Conversion
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PROBLEM DEFINITION
The Delta Sigma ADC outputs a count value symmetrical about 0, resulting in 2
the result is truncated to n bits, the maximum count is the same as the minimum count. It is interpreted as the
minimum count creating a discontinuity. For example, if you configure the ADC for an 8-bit result, you expect
values between 0x80 and 0x7F (-128 to +127). Instead the range is 0x80 to 0x80 (-128 to -128).
PARAMETERS AFFECTED
NA
TRIGGER CONDITION(S)
NA
SCOPE OF IMPACT
All Delta Sigma ADC conversions.
WORKAROUND
Two workarounds are possible. The recommended workaround is to read and use at least one more bit of
resolution from the ADC than the configured conversion requires. The extra bit ensures that the sign is properly
accounted for. For 6 and 7 bit conversions read an int8 value, for 8 to 12 bit conversions read an int16 value.
The second workaround is to ensure that the maximum count value is never reached by the ADC in the end
application.
FIX STATUS
Silicon revision fix confirmed in production silicon.
PROBLEM DEFINITION
End-of-Conversion (EOC) is signaled by a status register bit, decimator interrupt, decimator DMA, and DSI
routable signal. The DSI routable signal does not work. The CPU can poll the status register bit or use the
decimator interrupt or decimator DMA.
PARAMETERS AFFECTED
NA
TRIGGER CONDITION(S)
NA
SCOPE OF IMPACT
The ADC End-of-Conversion (EOC) output of the PSoC Creator component can only be used to route to one
DMA channel. The EOC output cannot be used to route through the DSI routing to any other digital resources.
The decimator DMA route bypasses the DSI routing avoiding this issue. The decimator interrupt integrated
into the PSoC Creator component also bypasses the DSI routing. All other possible EOC connections require
DSI routing.
WORKAROUND
The CPU can poll the EOC bit in the status register or use the decimator interrupt to signal the digital system
using firmware and a control register.
FIX STATUS
Silicon revision fix confirmed in production silicon
Document Number: 001-61136 Rev. *C
Errata Document
.
PSoC
®
n
+1 counts rather than 2
3: CY8C34 Family
n
. If
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