unsigned long clk;
int i;
+ /*
+ * PLL may not function properly at default LDO setting.
+ *
+ * Description:
+ *
+ * In designs that enable and use the PLL module, unstable device
+ * behavior may occur with the LDO set at its default of 2.5 volts or
+ * below (minimum of 2.25 volts). Designs that do not use the PLL
+ * module are not affected.
+ *
+ * Workaround: Prior to enabling the PLL module, it is recommended that
+ * the default LDO voltage setting of 2.5 V be adjusted to 2.75 V using
+ * the LDO Power Control (LDOPCTL) register.
+ *
+ * Silicon Revision Affected: A1, A2
+ *
+ * See also: Stellaris LM3S1968 A2 Errata documentation.
+ */
+ if (REVISION_IS_A1 | REVISION_IS_A2)
+ HWREG(SYSCTL_LDOPCTL) = SYSCTL_LDOPCTL_2_75V;
+
rcc = HWREG(SYSCTL_RCC);
rcc2 = HWREG(SYSCTL_RCC2);