JAJSOX0B March 2024 – November 2024 ADS127L18
PRODMIX
In the hardware programming mode, the device is programmed by strapping the pins to IOVDD, DGND or floated, but also can be tied to a controller I/O to change ADC configuration as needed. Hardware programming is selected by floating or grounding the MODE pin, in which SPI programing is disabled. Figure 7-43 and Table 7-16 show the hardware pins and the pin functionality. Not all device options are available in hardware mode. See the SPI Programming section for details of SPI programming.
PIN | NO. | DESCRIPTION | STATE(1) | FUNCTION | ||
---|---|---|---|---|---|---|
MODE | 54 | SPI or hardware programming mode | 0 | Hardware programming, all buffers ON | ||
1 | SPI programming | |||||
F | Hardware programming, all buffers OFF | |||||
CS/SPEED | 55 | Speed mode | 0 | Low-speed mode | ||
1 | Max-speed mode | |||||
F | Mid-speed mode | |||||
SCLK/FLTR | 56 | Filter type | 0 | Wideband filter | ||
1 | Low-latency sinc4 filter | |||||
F | Low-latency sinc4 + sinc1 filter | |||||
SDO/OSR1 SDI/OSR0 |
2,1 | Filter OSR | OSR1/OSR0 | WIDEBAND FILTER | SINC4 FILTER | SINC4 + SINC1 FILTER |
00 | 32 | 12 | 64 | |||
01 | 64 | 16 | 128 | |||
0F | 128 | 24 | 320 | |||
10 | 256 | 32 | 640 | |||
11 | 512 | 64 | 1280 | |||
1F | 1024 | 128 | 3200 | |||
F0 | 2048 | 256 | 6400 | |||
F1 | 4096 | 1024 | 12800 | |||
FF | 4096 | 4096 | 32000 | |||
GPIO0/TDM | 3 | Data port TDM | 0 | No TDM, four or eight data lanes (all DOUTx pins are used) | ||
1 | ADS127L18: one data lane (DOUT0 pin) | |||||
F | ADS127L14: one data
lane (DOUT0 pin) ADS127L18: two data lanes (DOUT0 and DOUT1 pins) |
|||||
GPIO1/HDR | 4 | Data-port header | 0 | 24 data bits (only) | ||
1 | STATUS header byte + 24 data bits | |||||
F | STATUS header byte + 24 data bits + CRC byte |
The device reads the pins at power-up and at device reset by applying pulses through a weak driver (ZOUT = 25kΩ). Make sure the pin levels are established prior to power-up or reset. If a floating condition is detected, the device drives the pin low to prevent the pin from floating during normal operation. After the pins are read, changes to the pins are not acknowledged until the next power up or reset cycle.
Because the device applies pulses to read the pins, the float-state condition limits the external pin capacitance and external leakage current. The logic 1 and 0 input conditions also limits the maximum pull-up and pull-down resistors. Figure 7-44 shows the electrical limits for each state. For proper pin mode detection, do not tie together floating inputs of other devices.
Programming options not available in the hardware mode assume the SPI register default values. See the Register Map section for the default values. Table 7-19 shows the exceptions to the SPI defaults.
FUNCTION | HARDWARE MODE DEFAULT |
---|---|
Clock mode | External clock |
Reference range | High reference range |
VCM output | Enabled |