Transport Layer
The module supports the automatic transmission and reception of multiple bytes. With the inbuilt DMA the TX data is take from or the RX data is written directly into the memory. For TX the firmware writes the payload into the memory and configures the module with payload start address and payload length. The module transfers the payload automatically and signalizes the end of the transmission with an interrupt. For RX the firmware configures the module with expected payload length and payload address. The module writes the received payload at the configured memory address. The number of received bytes is stored inside the module and interrupts for begin of transmission and end of transmission are generated.
ISO/IEC 7816-3 defines three types of data transport modes:
- Plain mode
- T = 0 mode
- T = 1 mode
Plain Mode
In plain mode, the module transmits or receives multiple bytes controlled by software. Thus the module is explicitly set in TX, RX or TX followed by RX mode.
T = 0 Mode
T = 0 mode is not implemented in hardware on purpose. SIM implementations vary in details. Therefore the implementation is done in firmware using plain mode.
T = 1 Mode
T = 1 mode is not implemented in hardware on purpose. SIM implementations vary in details. Therefore the implementation is done in firmware using plain mode.
