TRM-915-R250 datasheet(29/39 Pages) LINX

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Compatibility Mode - Address = 0x70; NV Address = 0x25

Compatibility mode allows the 250 Series modules to communicate with

the 25 Series modules. Please see the Compatibility Mode section for more

details. Figure 61 shows examples of the commands and Figure 62 shows

the available values.

Auto Addressing - Address = 0x71; NV Address = 0x26

When this register is enabled, the module reads the Source Address from

a received packet and uses it to fill the Destination Address registers.

This makes sure that a response is sent to the device that transmitted the

original message.

The non-volatile register only uses the lower 4 bits to configure the

automatic addressing. The upper 4 bits are not used.

The volatile register is split in half with the lower 4 bits configuring the

automatic addressing, the same as the non-volatile register.

The upper 4 bits indicate the type of packet that was last received. This

indication is the same as the Network Mode register setting. These bits

are not used by the module and are only written by the module after

successfully receiving a packet.

Figure 61: 250 Series Transceiver Compatibility Mode Command and Response

250 Series Compatibility Mode Register Settings

Mode

0x00

Disable Compatibility Mode

0x01

Enable Compatibility Mode

Figure 62: 250 Series Compatibility Mode Register Settings

250 Series Compatibility Mode

Read Command

Read Response

Header

Size

Escape

Address

ACK

Address

Value

0xFF

0x02

0xFE

0x70

0x25

0x06

0x70

0x25

Write Command

Header

Size

Address

Value

0xFF

0x02

0x70

0x25

Receiver LNA Mode - Address = 0x6F; NV Address = 0x24

By default, the module is factory-configured to use its internal Automatic

Gain Control (AGC) circuit to manage receiver sensitivity. Reducing the gain

increases the linearity of the receiver, but reduces maximum sensitivity;

increasing the gain does the opposite. Generally speaking, higher

linearity (increased third order input intercept point, IIP3) gives improved

performance in high-interference environments; high gain yields better

performance in low-interference environments.

The module contains an AGC circuit that manages these settings

automatically, and it should be used whenever possible. When reading the

digital RSSI registers (regIMMEDRSSI, regLGPRSSI), the internal calculation

automatically compensates for the current LNA gain setting. However,

when attempting to make analog RSSI measurements, fixing the LNA gain

produces more meaningful results.

Figure 59 shows examples of the commands and Figure 60 shows the

available values.

250 Series LNA Mode Register Settings

Meaning

IIP3 Increase

Sensitivity Decrease

0x00

AGC Enabled

Variable

0x01

High Sensitivity

Reference

0x02

Mid Linearity

19.1dB

6.5dB

0x03

High Linearity

41.8dB

9.5dB

Figure 59: 250 Series Transceiver LNA Mode Command and Response

Figure 60: 250 Series Transceiver LNA Mode Register Settings

250 Series LNA Mode

Read Command

Read Response

Header

Size

Escape

Address

ACK

Address

Value

0xFF

0x02

0xFE

0x6F

0x24

0x06

0x6F

0x24

Write Command

Header

Size

Address

Value

0xFF

0x02

0x6F

0x24

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