Other Parts Discussed in Thread: AFE4404,
Tool/software:
Hi,
1. According to the datasheet Table 18 page 27, the duration of ADC conversion phase is defined as t5 = (NUMAV + 1) * 200 * tADC + 15 microseconds
However, if we apply this formula to the example given in Table 22 for the case corresponding to CLK_INT=4Mhz, PRF=100, NUMAV=3, CLKDIV_PRF = 1 and a pulse duration of 100uS we should get:
LEDxCONVEND – LEDxCONVST = (3 + 1) * 200 * (1/4) + 15 = 215 microseconds. However, the difference in the table is 1058 clock counts or 264.5 microseconds.
This value seems to correspond better to the formula found on table 7 page 24 of the AFE4404 datasheet, where t5 is defined as = (NUMAV + 2) * 200 * tADC + 15 microseconds,
which, for the same case, would give a value of (3 + 2) * 200 * (1/4) + 15 = 265 microseconds
Which one is the correct value ? t5 as defined in the AFE4405 datasheet? t5 as defined in the AFE4404 datasheet ? or none of them ?
2. In the example given in table 22, ALED1STC is 1279 and ALED1ENDC is 1598. But when we apply the formulas from Table 18 and following, we find ALED1STC=1280 and ALED1ENDC=1599. Where does this 1 clock count difference come from?
3. Can you explain how to define DATA_RDY_STC / DATA_RDY_ENDC as the example in table 22 doesn’t seem to relate to any previous formula?
4. Could you please provide a timing example corresponding to the following case: CLK_INT=4Mhz, PRF=100, NUMAV=3, CLKDIV_PRF = 1, pulse duration of 100uS, LED3 only, and detection using PD2 ? When a LED is not used the AFE4405 datasheet page 27 suggests to set both the corresponding phase start and end counts to at least PRPCT+1 but doesn’t mention if ADCRSTx should sill be programmed and how, while AFE4404 datasheet page suggest to set the phase duration to 0 (but without saying that the start and end counts should be greater then PRPCT) and states that ADCRSTx shall be defined. What it is the correct way?
