External RF Amp with MKW21D256

[leper]

Hi,

We are developing products based upon the Kinetis MKW21D256 device. We're using an external RF front end with an external RF amp and an antenna diversity switch.

We’ve previously used the same external RF amp (CC2591) in similar products using the now superseded MC13224V.

We used Freescale Beekit to develop Kinetis code for the products.

The Beekit codebase provides Asp_ functions to configure the MKW21D256 RF front end, but there are no functions in the Asp_ library to configure for an external RF amp, i.e. to enable the operation of the MKW21D256 pins TX_SWITCH and RX_SWITCH.

There are functions in AppAspInterface.h provided to configure antenna diversity, but the Set functions appear to have no effect, they are:

uint8_t Asp_SetFADState(bool_t state);

bool_t Asp_GetFADState(void);

uint8_t Asp_SetFADThreshold(uint8_t thresholdFAD);

uint8_t Asp_GetFADThreshold(void);

uint8_t Asp_SetANTXState(bool_t state);

bool_t Asp_GetANTXState(void);

Is there any documentation describing how and when to configure the MKW21D256 for external RF Amp operation? Is there a document that describes the MKW21D256's bonded MC1324x 2.4 GHz transceiver?

We discovered http://cache.freescale.com/files/rf_if/doc/ref_manual/MCR20RM.pdf , which may be an an indication of how the MKW21D256 bonded MC1324x works.

Cheers,

Tim

[jc_pacheco · Accepted solution]

Hello Tim,

If you require to enable the MCR20A Antenna Control Signals (TX_Switch, RX_Switch, ANT_A, ANT_B), please take a look into the Fast Antenna Diversity chapter (Available in both MKW2xRM and MCR20RM) and the Antenna Control (Indirect Modem_ANT_PAD_CTRL) register

"Antenna PAD Control (Indirect Modem_ANT_PAD_CTRL, 0x30): This register sets the action on the pads ANTA, ANTB, RX_SWITCH and TX_SWITCH."

This is an example on how to interact with those registers:

Add xcvr headers:

/* Transceiver SPI functions and Registers */

#include "MCR20Drv.h"

#include "MCR20Reg.h"

.

.

.

MCR20Drv_IndirectAccessSPIWrite(ANT_PAD_CTRL,0x03);   /* ANT_PAD_CTRL -> Single mode/TxRx Sw, ants signals enable */

.

.

.

Regards,

JC

[leper]

Thanks JC,

We've got this going now, using the same register you described.

Regards,

Tim