Any tips or examples on using the UNO R4 TRNG and AES support ?
Hah. They don't seem to be documented, even in the Renesas "manuals."
The whole section describing the "secure crypto engine" is about 5 pages of feature lists and relatively useless block diagrams.
Hmm. I did find a relatively promising candidate HW_SCE_RNG_Read() in the fsp repository:
It claims to return 128bits of random number.
I can't figure out what it needs for a #include path, but the code might be a useful model. 
Ah. Apparently the Arduino distribution of fsp include files only includes SOME of the Renesad-provided include files, and that doesn't include the Crypto engine stuff (the TRNG is considered part of Crypto.)
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From fsp/ra/fsp/src/bsp/cmsis/Device/RENESAS/Include/R7FA2A1AB.h I pasted in the TRNG definitions into a sketch
// R4 TRNG
#define __IM volatile
#define R_TRNG_BASE 0x400D1000UL
#define R_TRNG ((R_TRNG_Type *) R_TRNG_BASE)
typedef struct /*!< (@ 0x400D1000) R_TRNG Structure */
{
union
{
__IM uint8_t TRNGSDR; /*!< (@ 0x00000000) TRNG SEED Data Register */
struct
{
__IM uint8_t SDATA : 8; /*!< [7..0] When RDRDY bit is 1, these bits hold the generated SEED.
When RDRDY bit is 0, these bits are read as 00h.The SEED
is generated as 32-bit data. When TRNGSDR is read 4 times
while RDRDY = 1, SEED reading is completed and RDRDY bit
changes to 0 */
} TRNGSDR_b;
};
__IM uint8_t RESERVED;
union
{
__IOM uint8_t TRNGSCR0; /*!< (@ 0x00000002) TRNG SEED Command Register 0 */
struct
{
uint8_t : 2;
__OM uint8_t SGSTART : 1; /*!< [2..2] SEED Generation Start */
__IOM uint8_t SGCEN : 1; /*!< [3..3] SEED Generation Circuit Enable */
uint8_t : 3;
__IM uint8_t RDRDY : 1; /*!< [7..7] When SEED geenration is completed, this bit changes to
0 */
} TRNGSCR0_b;
};
union
{
__IOM uint8_t TRNGSCR1; /*!< (@ 0x00000003) TRNG SEED Command Register 1 */
struct
{
__IOM uint8_t INTEN : 1; /*!< [0..0] TRNG Interrupt Enable */
uint8_t : 7;
} TRNGSCR1_b;
};
} R_TRNG_Type;
uint32_t trng() {
uint32_t rval;
uint8_t * ptmp = (uint8_t *) &rval;
/* Set SGCEN bit and SGSTART bit */
R_TRNG->TRNGSCR0_b.SGCEN = 1;
R_TRNG->TRNGSCR0_b.SGSTART = 1;
/* Wait for RDRDY bit to be set */
while (0 == R_TRNG->TRNGSCR0_b.RDRDY)
{
}
/* Read generated random data */
*ptmp++ = R_TRNG->TRNGSDR;
*ptmp++ = R_TRNG->TRNGSDR;
*ptmp++ = R_TRNG->TRNGSDR;
*ptmp++ = R_TRNG->TRNGSDR;
return rval;
}
void setup() {
Serial.begin(9600);
while (!Serial);
}
void loop() {
Serial.println(trng(), HEX);
delay(500);
}
the sketch compiles, but I don't have my R4 yet, so I can't test.
i got my R4 board, but I couldn't get the TRNG sketch to work. I tried two different BASE ADDRESS.
must be other steps required to start the TRNG ?? TODO
Any new information? The old Arduino lacked a high-quality random generator.
I'll share a sample code using the TRNG from SCE5.
#ifdef __cplusplus
extern "C" {
#endif
#include <hw_sce_private.h>
#include <hw_sce_trng_private.h>
#ifdef __cplusplus
}
#endif
uint32_t rnd[4] = { 0 };
fsp_err_t err = FSP_ERR_ASSERTION;
void setup() {
Serial.begin(115200);
while (!Serial)
;
Serial.println("PowerOn");
HW_SCE_PowerOn();
Serial.println("MCU Specific Init.");
err = HW_SCE_McuSpecificInit();
if (err != FSP_SUCCESS) {
Serial.println("MSU Specific Init failed!");
delay(5000);
} else {
Serial.println("MCU Specific Init done.");
Serial.println("SCE5 setup complete.");
}
}
void loop() {
err = HW_SCE_RNG_Read(rnd);
if (err != FSP_SUCCESS) {
Serial.print("failed HW_SCE_RNG_Read: ");
Serial.println(err, HEX);
} else {
char s[33] = {0};
sprintf(s, "%08X%08X%08X%08X", rnd[0], rnd[1], rnd[2], rnd[3]);
Serial.println(s);
}
delay(1000);
}
Before compiling, it's important to note that the r_sce_if.h header file included in the Arduino IDE's Board Manager contains C++ reserved words. Therefore, you'll need to manually modify the header file as follows (since this header file is almost always necessary when using SCE5, it can cause compilation errors everywhere )
/* RSA 1024bit key index pair structure */
typedef struct sce_rsa1024_key_pair_index
{
sce_rsa1024_private_key_index_t priv_key; // Changed 'private' to 'priv_key'
sce_rsa1024_public_key_index_t pub_key; // Changed 'public' to 'pub_key'
} sce_rsa1024_key_pair_index_t;
There are other parts in this file that use private and public , so please make similar changes.
Additionally, r_sce_if.h is located at the following paths (I apologize, as I am a MacOS user, I am not sure about Windows):
for MINIMA:
/Users/{username}/Library/Arduino15/packages/arduino/hardware/renesas_uno/1.1.0/variants/MINIMA/includes/ra/fsp/src/r_sce/crypto_procedures/src/sce5/plainkey/public/inc/r_sce_if.h
for WiFi version:
/Users/{username}/Library/Arduino15/packages/arduino/hardware/renesas_uno/1.1.0/variants/UNOWIFIR4/includes/ra/fsp/src/r_sce/crypto_procedures/src/sce5/plainkey/public/inc/r_sce_if.h
This is my article summarizing the above: Exploring the Hardware Random Number Generator of Arduino R4 MINIMA | blog.jetzou.com
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I reported the issue at GitHub - renesas/fsp: Flexible Software Package (FSP) for Renesas RA MCU Family and was told it would be fixed in the release scheduled for the end of May 2024, likely v5.4.0. (see: Using SCE5 in a C++project causes a build error · Issue #353 · renesas/fsp · GitHub)
However, I'm not sure when this will be reflected in GitHub - arduino/ArduinoCore-renesas. Is this repository always tracking the renesas/fsp repository? If not, I'm wondering whether I should also raise an issue at arduino/ArduinoCore-renesas. If anyone knows what actions I should take, please let me know.