Mainly A quick Reference for myself. This information was gathered from the "SNAP Hardware Technical Manual" version 1.3 DOC# 600-101.01D. Unfortunately It now turns out this document disagrees with the "SNAP Reference Manual" version 2.4 DOC# 600-0007G.

Public Message to Synapse Wireless: If you would provide this, I would not need to.

But, in the meantime, here is the side-by-side comparison of RF Engine pin outs. If it helps you, please leave a comment.

pin num rf100 rf200 rf300 I2C SPI
1 GND GND GND
2 GPIO0_TPM1CH2 GPIO0 OC0A OC1C PCINT7 PB7 GPIO0 ADC17 P2.1 SDA rf300-sda
3 GPIO1_KBI0 GPIO1 OC1B PCINT6 PB6 GPIO1 ADC18 P2.2 SCL rf300-scl
4 GPIO2_KBI1 GPIO2 OC1A PCINT5 PB5 GPIO2 ADC19 P2.3
5 GPIO3_RX_UART0 GPIO3 RXD0 PCINT8 PE0 GPIO3 ADC20 P2.4
6 GPIO4_TX_UART0 GPIO4 TXD0 PE1 GPIO4 ADC21 P2.5
7 GPIO5_KBI4_CTS0 GPIO5 OC3B INT4 PE4 GPIO5 ADC22 P2.6
8 GPIO6_KBI5_RTS0 GPIO6 OC3C INT5 PE5 GPIO6 ADC0 P0.0 VREF
9 GPIO7_RX_UART1 GPIO7 RXD1 INT2 PD2 GPIO7 ADC5 P0.5 UARTRX
10 GPIO8_TX_UART1 GPIO8 TXD1 INT3 PD3 GPIO8 ADC4 P0.4 UARTTX
11 GPIO9_KBI6_CTS1 GPIO9 CTS1 ICP1 PD4 GPIO9 ADC3 P0.3 CTS
12 GPIO10_KBI7_RTS1 GPIO10 RTS1 ICP3 INT7 CLKO GPIO10 ADC2 P0.2 RTS
13 GPIO11_AD7 GPIO11 ADC0 SCL PF0 GPIO11 ADC16 P2.0 rf200-scl
14 GPIO12_AD6 GPIO12 ADC1 SDA PF1 GPIO12 ADC15 P1.7 rf200-sda rf300-mosi rf100-mosi
15 GPIO13_AD5 GPIO13 ADC2 DIG2 PF2 GPIO13 ADC13 P1.5 rf300-sclk rf100-sclk
16 GPIO14_AD4 GPIO14 XCK0 AIN0 PE2 GPIO14 ADC14 P1.6 rf300-miso rf100-miso
17 GPIO15_AD3 GPIO15 ADC4 TCK MISO PF4 GPIO15 ADC6 P0.6 CNVSTR rf200-miso
18 GPIO16_AD2 GPIO16 ADC5 TMS SCLK PF5 GPIO16 P2.7 rf200-sclk
19 GPIO17_AD1 GPIO17 ADC6 TDO MOSI PF6 GPIO17 (GPIO_0) rf100-sda rf200-mosi
20 GPIO18_AD0 GPIO18 ADC7 TDI PF7 ANT_A rf100-scl
21 VCC VCC VCC
22 PTG0/BKDG GPIO19 OC3A AIN1 PE3 C2D
23 RESET RESET RESET
24 GND GND GND