This is a known issue in the ES2 silicon for PSoC 3 and PSoC 5. This issue is not applicable to PSoC 3 ES3 or PSoC 5LP Production Release silicon. VIDAC0 does not operate correctly when its output is greater than 2.4 V. The other three DACs work according to specifications.
Figure 1. Selecting DAC Block in PSoC Creator 2.1
For PSoC Creator versions prior to 2.1, use the following procedure. In this example, the instance name of the VDAC8 in question is “VDAC8_1”. Refer to Figure 2 or do the following:
/* VDAC8_1_viDAC8 */
#define VDAC8_1_viDAC8__CR0 CYREG_DAC1_CR0
This confirms that the viDAC8 used is now DAC1 instead of DAC0
Figure 2. PSoC Creator Directives Tab
Refer to the errata document of PSoC 3 (ES2) and PSoC 5 (ES1) for more details.