Silicon Laboratories Finland WT41U WT41 long range Bluetooth 2.1+EDR module User Manual Product Data Sheet
Silicon Laboratories Finland Oy WT41 long range Bluetooth 2.1+EDR module Product Data Sheet
Contents
- 1. Users Manual
- 2. Data Sheet
- 3. User manual 1 of 2
- 4. User manual 2 of 2
Users Manual







![Silicon Laboratories Finland Oy Page 8 of 45 Pad name Pad number Pad type Description NC 1, 52 Not connected Pins 1 and 52 are not present on the footprint RESET 33 Digital input Active low reset with weak internal pull-up. Keep low for >5ms to reset module GND 2-10, 16, 23, 24, 26-28, 30, 31, 36, 44-49, 53-59 Ground Ground pads should all be connected to a ground plane with minimum trace length, especially on the antenna end of the module RF 51 Not connected No internal connection RFGND 50 Ground Connect to ground plane VDD_PA 11 Supply voltage Supply voltage for the RF power amplifier and low noise amplifier VDD 32 Supply voltage Supply voltage for the Bluetooth chipset Table 2: Supply and RF Terminal Descriptions PIO signal Pad number Description PIO[2] 12 Bi-directional digital in/out with programmable strength and pull-up/pull-down PIO[3] 13 Bi-directional digital in/out with programmable strength and pull-up/pull-down PIO[4] 29 Bi-directional digital in/out with programmable strength and pull-up/pull-down PIO[5] 41 Bi-directional digital in/out with programmable strength and pull-up/pull-down PIO[6] 34 Bi-directional digital in/out with programmable strength and pull-up/pull-down PIO[7] 35 Bi-directional digital in/out with programmable strength and pull-up/pull-down AIO[1] 43 Bi-directional analog in/out Table 3: GPIO Terminal Descriptions](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-8.png)












![Silicon Laboratories Finland Oy Page 21 of 45 Equation 1: Data Rate Data rate [bits/s] Persistent store value (Hex) Error [bits/s] Error [%] 1200 0x0005 5 1.73 2400 0x000A 10 1.73 4800 0x0014 20 1.73 9600 0x0027 39 -0.82 19200 0x004F 79 0.45 38400 0x009D 157 -0.18 57600 0x00EC 236 0.03 76800 0x013B 315 0.14 115200 0x01D8 472 0.03 230400 0x03B0 944 0.03 460800 0x075F 1887 -0.02 921600 0x0EBF 3775 0 1382400 0x161E 5662 -0.01 1843200 0x1D7E 7550 0 2764800 0x2C3D 11325 0 Table 14: Standard Data Rates](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-21.png)
![Silicon Laboratories Finland Oy Page 22 of 45 6.1 UART Bypass Figure 12: UART Bypass Architecture 6.2 UART Configuration While Reset is Active The UART interface for WT41u while the chip is being held in reset is tristate. This will allow the user to daisy chain devices onto the physical UART bus. The constraint on this method is that any devices connected to this bus must tristate when WT41u reset is de-asserted and the firmware begins to run. 6.3 UART Bypass Mode Alternatively, for devices that do not tristate the UART bus, the UART bypass mode on the chipset can be used. The default state of the chipset after reset is de-asserted; this is for the host UART bus to be connected to the chipset UART, thereby allowing communication to the chipset via the UART. All UART bypass mode connections are implemented using CMOS technology and have signalling levels of 0V and VDD. In order to apply the UART bypass mode, a BCCMD command will be issued to the chipset. Upon this issue, it will switch the bypass to PIO[7:4] as Figure 11 indicates. Once the bypass mode has been invoked, WT41u will enter the Deep Sleep state indefinitely. In order to re-establish communication with WT41u, the chip must be reset so that the default configuration takes effect. It is important for the host to ensure a clean Bluetooth disconnection of any active links before the bypass mode is invoked. Therefore, it is not possible to have active Bluetooth links while operating the bypass mode. The current consumption for a device in UART bypass mode is equal to the values quoted for a device in standby mode.](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-22.png)











![Silicon Laboratories Finland Oy Page 34 of 45 Name Bit position Description - 0 Set to 0 SLAVE MODE EN 1 0 selects Master mode with internal generation of PCM_CLK and PCM_SYNC. 1 selects Slave mode requiring externally generated PCM_CLK and PCM_SYNC. This should be set to 1 if 48M_PCM_CLK_GEN_EN (bit 11) is set. SHORT SYNC EN 2 0 selects long frame sync (rising edge indicates start of frame), - 3 Set to 0 SIGN EXTENDED EN 4 0 selects long frame sync (rising edge indicates start of frame), 1 selects short frame sync (falling edge indicates start of frame). LSB FIRST EN 5 0 transmits and receives voice samples MSB first, 1 uses LSB TX TRISTATE EN 6 0 transmits and receives voice samples MSB first, 1 uses LSB TX TRISTATE RISING EDGE EN 7 0 tristates PCM_OUT immediately after the falling edge of PCM_CLK in the last bit of an active slot, assuming the next slot is also not active. 1 tristates PCM_OUT after the rising edge of PCM_CLK. SYNC SUPPRESS EN 8 0 enables PCM_SYNC output when master, 1 suppresses PCM_SYNC whilst keeping PCM_CLK running. Some CODECS utilize this to enter a low power state GCI MODE EN 9 1 enables GCI mode. MUTE EN 10 1 forces PCM_OUT to 0. 48M PCM CLK GEN EN 11 0 sets PCM_CLK and PCM_SYNC generation via DDS from internal 4 MHz clock. 1 sets PCM_CLK and PCM_SYNC generation via DDS from internal 48 MHz clock. LONG LENGTH SYNC EN 12 0 sets PCM_SYNC length to 8 PCM_CLK cycles and 1 sets length to 16 PCM_CLK cycles. Only applies for long frame sync and with 48M_PCM_CLK_GEN_EN set to 1. - [20:16] Set to 0b00000. MASTER CLK RATE [22:21] Selects 128 (0b01), 256 (0b00), 512 (0b10) kHz PCM_CLK frequency when master and 48M_PCM_CLK_GEN_EN (bit 11) is low. ACTIVE SLOT [26:23] Default is 0001. Ignored by firmaware SAMPLE FORMAT [28:27] Selects between 13 (0b00), 16 (0b01), 8 (0b10) bit sample with 16 cycle slot duration 8 (0b11) bit sample 8 cycle slot duration. Table 15: PSKEY_PCM_CONFIG32 description](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-34.png)
![Silicon Laboratories Finland Oy Page 35 of 45 Name Bit position Description CNT LIMIT [12:0] Sets PCM_CLK counter limit CNT RATE [23:16] Sets PCM_CLK count rate SYNC LIMIT [31:24] Sets PCM_SYNC division relative to PCM_CLK Table 16: PSKEY_PCM_LOW_JITTER_CONFIG Description](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-35.png)
![Silicon Laboratories Finland Oy Page 36 of 45 10 I/O Parallel Ports Six lines of programmable bidirectional input/outputs (I/O) are provided. All the PIO lines are power from VDD. PIO lines can be configured through software to have either weak or strong pull-ups or pull-downs. All PIO lines are configured as inputs with weak pull-downs at reset. Any of the PIO lines can be configured as interrupt request lines or as wake-up lines from sleep modes. WT41u has a general purpose analogue interface pin AIO[1]. This is used to access internal circuitry and control signals. It may be configured to provide additional functionality. Auxiliary functions available via AIO[1] include an 8-bit ADC and an 8-bit DAC. Typically the ADC is used for battery voltage measurement. Signals selectable at this pin include the band gap reference voltage and a variety of clock signals: 48, 24, 16, 8MHz and the XTAL clock frequency. When used with analogue signals, the voltage range is constrained by the analogue supply voltage internally to the module (1.8V). When configured to drive out digital level signals (e.g., clocks), the output voltage level is determined by VDD. 10.1 PIO Defaults Silicon Labs cannot guarantee that these terminal functions remain the same. Refer to the software release note for the implementation of these PIO lines, as they are firmware build-specific.](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-36.png)

![Silicon Laboratories Finland Oy Page 38 of 45 11.1 Pin States on Reset Pad name State PIO[7:2] Input, weak pull-down PCM_OUT 3-state, weak pull-down PCM_IN Input, weak pull-down PCM_SYNC Input, weak pull-down PCM_CLK Input, weak pull-down UART_TX 3-state, weak pull-up UART_RX Input, weak pull-down UART_RTS 3-state, weak pull-up UART_CTS Input, weak pull-down USB+ Input, weak pull-down USB- Input, weak pull-down SPI_CSB Input, weak pull-down SPI_CLK Input, weak pull-down SPI_MOSI Input, weak pull-down SPI_MISO 3-state, weak pull-down AIO[1] Output, driving low Table 17: Pin States on Reset](https://usermanual.wiki/Silicon-Laboratories-Finland/WT41U.Users-Manual/User-Guide-3202782-Page-38.png)






