at32f43x: Add detection of AT32F423 and basic support

src/target/at32f43x.c

@@ -331,6 +331,33 @@ static bool at32f405_detect(target_s *target, const uint32_t series)
 	return true;
 }
 
+static bool at32f423_detect(target_s *target, const uint32_t series)
+{
+	/*
+	 * AT32F423 always has 48 KiB of SRAM and one of
+	 * Flash (C): 256 KiB, 2 KiB per sector, 0x700a_3000
+	 * Flash (B): 128 KiB, 1 KiB per sector, 0x700a_2000
+	 * Flash (8):  64 KiB, 1 KiB per sector, 0x7003_2000
+	 */
+	const uint16_t flash_size = target_mem32_read16(target, AT32F4x_FLASHSIZE);
+	const uint16_t sector_size = (series == AT32F423_SERIES_256KB) ? 2048U : 1024U;
+	at32f43_add_flash(target, 0x08000000, flash_size, sector_size, 0, AT32F43x_FLASH_BANK1_REG_OFFSET);
+
+	target_add_ram32(target, 0x20000000, 48U * 1024U);
+	target->driver = "AT32F423";
+	target->mass_erase = at32f43_mass_erase;
+
+	/* 512 byte User System Data area at 0x1fff_f800 (different USD_BASE, no EOPB0) */
+	//target_add_commands(target, at32f43_cmd_list, target->driver);
+
+	/* Same registers and freeze bits in DBGMCU as F437 */
+	target->attach = at32f43_attach;
+	target->detach = at32f43_detach;
+	at32f43_configure_dbgmcu(target);
+
+	return true;
+}
+
 /* Identify AT32F43x "High Performance" line devices (Cortex-M4) */
 bool at32f43x_probe(target_s *target)
 {
@@ -354,7 +381,7 @@ bool at32f43x_probe(target_s *target)
 		return at32f405_detect(target, series);
 	if ((series == AT32F423_SERIES_256KB || series == AT32F423_SERIES_128KB || series == AT32F423_SERIES_64KB) &&
 		project_id == 0x12U)
-		return false;
+		return at32f423_detect(target, series);
 
 	return false;
 }